UBUNTU-CVE-2026-43383: Medium severity ubuntu/linux vulnerability

Q: Which Ubuntu kernel package families are listed as affected?

The listed package families are ubuntu/linux, ubuntu/linux-fips, ubuntu/linux-aws, ubuntu/linux-azure, ubuntu/linux-aws-fips, ubuntu/linux-azure-fips, ubuntu/linux-gcp, and ubuntu/linux-gcp-fips.

Q: What condition is relevant to exploiting this issue?

The issue concerns timing attacks against TCP MD5 MAC comparison. Exploitation would rely on observing timing differences produced by a non-constant-time MAC comparison.

Q: What is the remediation described for this vulnerability?

The resolved fix changes TCP MD5 MAC comparison to use an appropriate constant-time comparison helper function.

Published May 8, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved: net/tcp-md5: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.

Affected Software

244 affected componentsFixes available

ubuntu/linux<3.13.0-214.265

3.13.0-214.265

ubuntu/linux-aws<4.4.0-1156.162

4.4.0-1156.162

ubuntu/linux-azure<4.15.0-1205.220~14.04.1

4.15.0-1205.220~14.04.1

ubuntu/linux-lts-xenial<4.4.0-283.317~14.04.1

4.4.0-283.317~14.04.1

ubuntu/linux<4.4.0-283.317

4.4.0-283.317

ubuntu/linux-aws<4.4.0-1194.209

4.4.0-1194.209

ubuntu/linux-aws-hwe<4.15.0-1194.207~16.04.1

4.15.0-1194.207~16.04.1

ubuntu/linux-azure<4.15.0-1204.219~16.04.1

4.15.0-1204.219~16.04.1

ubuntu/linux-gcp<4.15.0-1187.204~16.04.1

4.15.0-1187.204~16.04.1

ubuntu/linux-hwe<4.15.0-253.265~16.04.1

4.15.0-253.265~16.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-kvm<4.4.0-1157.168

4.4.0-1157.168

ubuntu/linux-oracle<4.15.0-1156.167~16.04.1

4.15.0-1156.167~16.04.1

ubuntu/linux-fips<4.4.0-1126.133

4.4.0-1126.133

ubuntu/linux-fips*

ubuntu/linux<4.15.0-253.265

4.15.0-253.265

ubuntu/linux-aws<4.15.0-1194.207

4.15.0-1194.207

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4<5.4.0-1161.172~18.04.1

5.4.0-1161.172~18.04.1

ubuntu/linux-azure*

ubuntu/linux-azure-4.15<4.15.0-1204.219

4.15.0-1204.219

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4<5.4.0-1166.172~18.04.1

5.4.0-1166.172~18.04.1

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15<4.15.0-1187.204

4.15.0-1187.204

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4<5.4.0-1164.173~18.04.1

5.4.0-1164.173~18.04.1

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4<5.4.0-233.253~18.04.1

5.4.0-233.253~18.04.1

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4<5.4.0-1107.112~18.04.1

5.4.0-1107.112~18.04.1

ubuntu/linux-kvm<4.15.0-1176.181

4.15.0-1176.181

ubuntu/linux-oem*

ubuntu/linux-oracle<4.15.0-1156.167

4.15.0-1156.167

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4<5.4.0-1159.169~18.04.1

5.4.0-1159.169~18.04.1

ubuntu/linux-raspi-5.4<5.4.0-1144.157~18.04.1

5.4.0-1144.157~18.04.1

ubuntu/linux-aws-fips<4.15.0-2132.138

4.15.0-2132.138

ubuntu/linux-azure-fips<4.15.0-2112.118

4.15.0-2112.118

ubuntu/linux-fips<4.15.0-1149.161

4.15.0-1149.161

ubuntu/linux-gcp-fips<4.15.0-2095.101

4.15.0-2095.101

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.4.0-233.253

5.4.0-233.253

ubuntu/linux-aws<5.4.0-1161.172

5.4.0-1161.172

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1111.118~20.04.1

5.15.0-1111.118~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure<5.4.0-1166.172

5.4.0-1166.172

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1116.125~20.04.1

5.15.0-1116.125~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1116.125~20.04.1

5.15.0-1116.125~20.04.1

ubuntu/linux-bluefield<5.4.0-1120.127

5.4.0-1120.127

ubuntu/linux-gcp<5.4.0-1164.173

5.4.0-1164.173

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1111.121~20.04.1

5.15.0-1111.121~20.04.1

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.15<5.15.0-185.195~20.04.1

5.15.0-185.195~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm<5.4.0-1107.112

5.4.0-1107.112

ubuntu/linux-ibm-5.15<5.15.0-1105.109~20.04.1

5.15.0-1105.109~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1106.112~20.04.1

5.15.0-1106.112~20.04.1

ubuntu/linux-iot<5.4.0-1065.68

5.4.0-1065.68

ubuntu/linux-kvm<5.4.0-1148.157

5.4.0-1148.157

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-183.193~20.04.1

5.15.0-183.193~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1063.63~20.04.1

5.15.0-1063.63~20.04.1

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle<5.4.0-1159.169

5.4.0-1159.169

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1108.114~20.04.1

5.15.0-1108.114~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi<5.4.0-1144.157

5.4.0-1144.157

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1105.109~20.04.1

5.15.0-1105.109~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp<5.4.0-1079.83

5.4.0-1079.83

ubuntu/linux-aws-fips<5.4.0-1161.172+fips1

5.4.0-1161.172+fips1

ubuntu/linux-azure-fips<5.4.0-1166.172+fips1

5.4.0-1166.172+fips1

ubuntu/linux-fips<5.4.0-1135.145

5.4.0-1135.145

ubuntu/linux-gcp-fips<5.4.0-1164.173+fips1

5.4.0-1164.173+fips1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-185.195

5.15.0-185.195

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1111.118

5.15.0-1111.118

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1060.63~22.04.1

6.8.0-1060.63~22.04.1

ubuntu/linux-azure<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1063.71~22.04.1

6.8.0-1063.71~22.04.1

ubuntu/linux-azure-fde<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1062.69~22.04.1

6.8.0-1062.69~22.04.1

ubuntu/linux-gcp<5.15.0-1111.121

5.15.0-1111.121

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1063.69~22.04.1

6.8.0-1063.69~22.04.1

ubuntu/linux-gke<5.15.0-1107.113

5.15.0-1107.113

ubuntu/linux-gkeop<5.15.0-1094.102

5.15.0-1094.102

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-136.136~22.04.1

6.8.0-136.136~22.04.1

ubuntu/linux-ibm<5.15.0-1105.109

5.15.0-1105.109

ubuntu/linux-ibm-6.8<6.8.0-1060.61~22.04.1

6.8.0-1060.61~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1106.112

5.15.0-1106.112

ubuntu/linux-kvm<5.15.0-1103.108

5.15.0-1103.108

ubuntu/linux-lowlatency<5.15.0-183.193

5.15.0-183.193

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-134.134.1~22.04.1

6.8.0-134.134.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1106.107

5.15.0-1106.107

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1058.61~22.04.1

6.8.0-1058.61~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1063.63

5.15.0-1063.63

ubuntu/linux-nvidia-tegra-igx<5.15.0-1052.52

5.15.0-1052.52

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1108.114

5.15.0-1108.114

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1057.58~22.04.1

6.8.0-1057.58~22.04.1

ubuntu/linux-raspi<5.15.0-1105.108

5.15.0-1105.108

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-134.134~22.04.1

6.8.0-134.134~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1074.78

5.15.0-1074.78

ubuntu/linux-bluefield<5.15.0-1095.97

5.15.0-1095.97

ubuntu/linux-intel-iot-realtime<5.15.0-1103.105

5.15.0-1103.105

ubuntu/linux-realtime<5.15.0-1110.119

5.15.0-1110.119

ubuntu/linux-realtime-6.8<6.8.1-1055.56~22.04.1

6.8.1-1055.56~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1111.118+fips1

5.15.0-1111.118+fips1

ubuntu/linux-azure-fips<5.15.0-1116.125+fips1

5.15.0-1116.125+fips1

ubuntu/linux-fips<5.15.0-185.195+fips1

5.15.0-185.195+fips1

ubuntu/linux-gcp-fips<5.15.0-1111.121+fips1

5.15.0-1111.121+fips1

ubuntu/linux<6.8.0-134.134

6.8.0-134.134

ubuntu/linux-aws<6.8.0-1060.63

6.8.0-1060.63

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17<6.17.0-1019.19~24.04.1

6.17.0-1019.19~24.04.1

ubuntu/linux-azure<6.8.0-1063.71

6.8.0-1063.71

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17<6.17.0-1021.21~24.04.1

6.17.0-1021.21~24.04.1

ubuntu/linux-azure-fde<6.8.0-1062.69

6.8.0-1062.69

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1063.69

6.8.0-1063.69

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-6.17<6.17.0-1020.22~24.04.1

6.17.0-1020.22~24.04.1

ubuntu/linux-gke<6.8.0-1058.64

6.8.0-1058.64

ubuntu/linux-gkeop<6.8.0-1045.48

6.8.0-1045.48

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17<6.17.0-40.40~24.04.1

6.17.0-40.40~24.04.1

ubuntu/linux-ibm<6.8.0-1060.61

6.8.0-1060.61

ubuntu/linux-lowlatency<6.8.0-134.134.1

6.8.0-134.134.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1058.61

6.8.0-1058.61

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17<6.17.0-1026.26

6.17.0-1026.26

ubuntu/linux-nvidia-lowlatency<6.8.0-1058.61.1

6.8.0-1058.61.1

ubuntu/linux-nvidia-tegra<6.8.0-1029.30

6.8.0-1029.30

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17<6.17.0-1028.28

6.17.0-1028.28

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1057.58

6.8.0-1057.58

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17<6.17.0-1018.18~24.04.1

6.17.0-1018.18~24.04.1

ubuntu/linux-raspi<6.8.0-1060.64

6.8.0-1060.64

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-vmware<6.8.0-1008.8

6.8.0-1008.8

ubuntu/linux-xilinx<6.8.0-1032.33

6.8.0-1032.33

ubuntu/linux-bluefield<6.8.0-1026.30

6.8.0-1026.30

ubuntu/linux-raspi-realtime<6.8.0-2049.50

6.8.0-2049.50

ubuntu/linux-realtime<6.8.1-1055.56

6.8.1-1055.56

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17<6.17.0-1017.19~24.04.1

6.17.0-1017.19~24.04.1

ubuntu/linux-aws-fips<6.8.0-1060.63+fips1

6.8.0-1060.63+fips1

ubuntu/linux-azure-fips<6.8.0-1062.69+fips1

6.8.0-1062.69+fips1

ubuntu/linux-fips<6.8.0-134.134+fips1

6.8.0-134.134+fips1

ubuntu/linux-gcp-fips<6.8.0-1063.69+fips1

6.8.0-1063.69+fips1

ubuntu/linux<6.17.0-40.40

6.17.0-40.40

ubuntu/linux-aws<6.17.0-1019.19

6.17.0-1019.19

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<6.17.0-1020.22

6.17.0-1020.22

ubuntu/linux-oracle<6.17.0-1018.18

6.17.0-1018.18

ubuntu/linux-raspi<6.17.0-1021.21

6.17.0-1021.21

ubuntu/linux-realtime<6.17.0-1017.19

6.17.0-1017.19

ubuntu/linux-riscv<6.17.0-40.40.1

6.17.0-40.40.1

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 3.13.0-214.265
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1156.162
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1205.220~14.04.1
Upgrade
Upgrade ubuntu/linux-lts-xenial to a version that resolves this vulnerability.
Fixed in 4.4.0-283.317~14.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.4.0-283.317
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.4.0-1194.209
Upgrade
Upgrade ubuntu/linux-aws-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-1194.207~16.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 4.15.0-1204.219~16.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 4.15.0-1187.204~16.04.1
Upgrade
Upgrade ubuntu/linux-hwe to a version that resolves this vulnerability.
Fixed in 4.15.0-253.265~16.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.4.0-1157.168
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1156.167~16.04.1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.4.0-1126.133
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 4.15.0-253.265
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 4.15.0-1194.207
Upgrade
Upgrade ubuntu/linux-aws-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1161.172~18.04.1
Upgrade
Upgrade ubuntu/linux-azure-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1204.219
Upgrade
Upgrade ubuntu/linux-azure-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1166.172~18.04.1
Upgrade
Upgrade ubuntu/linux-gcp-4.15 to a version that resolves this vulnerability.
Fixed in 4.15.0-1187.204
Upgrade
Upgrade ubuntu/linux-gcp-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1164.173~18.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-233.253~18.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1107.112~18.04.1
Upgrade
Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 4.15.0-1176.181
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 4.15.0-1156.167
Upgrade
Upgrade ubuntu/linux-oracle-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1159.169~18.04.1
Upgrade
Upgrade ubuntu/linux-raspi-5.4 to a version that resolves this vulnerability.
Fixed in 5.4.0-1144.157~18.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2132.138
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2112.118
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-1149.161
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 4.15.0-2095.101
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.4.0-233.253
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.4.0-1161.172
Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.118~20.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.4.0-1166.172
Upgrade
Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125~20.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125~20.04.1
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.4.0-1120.127
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.4.0-1164.173
Upgrade
Upgrade ubuntu/linux-gcp-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.121~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-185.195~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 5.4.0-1107.112
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1105.109~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.112~20.04.1
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Fixed in 5.4.0-1065.68
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Fixed in 5.4.0-1148.157
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Fixed in 5.15.0-183.193~20.04.1
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Fixed in 5.15.0-1063.63~20.04.1
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Fixed in 5.4.0-1159.169
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Fixed in 5.15.0-1108.114~20.04.1
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Fixed in 5.4.0-1144.157
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Fixed in 5.15.0-1105.109~20.04.1
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Fixed in 5.4.0-1079.83
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Fixed in 5.4.0-1161.172+fips1
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Fixed in 5.4.0-1166.172+fips1
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Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.4.0-1135.145
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Fixed in 5.4.0-1164.173+fips1
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Fixed in 5.15.0-185.195
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Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.118
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Fixed in 6.8.0-1060.63~22.04.1
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Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125
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Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.71~22.04.1
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Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1116.125
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Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1062.69~22.04.1
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.121
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Fixed in 6.8.0-1063.69~22.04.1
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Fixed in 5.15.0-1107.113
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Fixed in 5.15.0-1094.102
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Fixed in 6.8.0-136.136~22.04.1
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Fixed in 5.15.0-1105.109
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Fixed in 6.8.0-1060.61~22.04.1
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Fixed in 5.15.0-1106.112
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Upgrade ubuntu/linux-kvm to a version that resolves this vulnerability.
Fixed in 5.15.0-1103.108
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-183.193
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Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-134.134.1~22.04.1
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Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.107
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Fixed in 6.8.0-1058.61~22.04.1
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Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 5.15.0-1063.63
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Fixed in 5.15.0-1052.52
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Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 5.15.0-1108.114
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Fixed in 6.8.0-1057.58~22.04.1
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Fixed in 5.15.0-1105.108
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Fixed in 6.8.0-134.134~22.04.1
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Fixed in 5.15.0-1074.78
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Fixed in 5.15.0-1095.97
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Fixed in 5.15.0-1103.105
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Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1110.119
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Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1055.56~22.04.1
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Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.118+fips1
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Fixed in 5.15.0-1116.125+fips1
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Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-185.195+fips1
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Fixed in 5.15.0-1111.121+fips1
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Fixed in 6.8.0-134.134
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Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1060.63
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Upgrade ubuntu/linux-aws-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1019.19~24.04.1
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Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.71
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Upgrade ubuntu/linux-azure-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1021.21~24.04.1
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Fixed in 6.8.0-1062.69
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.69
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Upgrade ubuntu/linux-gcp-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1020.22~24.04.1
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Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.64
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1045.48
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Upgrade ubuntu/linux-hwe-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-40.40~24.04.1
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Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1060.61
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-134.134.1
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Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1058.61
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Upgrade ubuntu/linux-nvidia-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1026.26
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Fixed in 6.8.0-1058.61.1
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Fixed in 6.8.0-1029.30
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Upgrade ubuntu/linux-oem-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1028.28
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Fixed in 6.8.0-1057.58
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Fixed in 6.17.0-1018.18~24.04.1
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Fixed in 6.8.0-1060.64
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Upgrade ubuntu/linux-vmware to a version that resolves this vulnerability.
Fixed in 6.8.0-1008.8
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Fixed in 6.8.0-1032.33
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Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 6.8.0-1026.30
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Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2049.50
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Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1055.56
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Upgrade ubuntu/linux-realtime-6.17 to a version that resolves this vulnerability.
Fixed in 6.17.0-1017.19~24.04.1
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Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1060.63+fips1
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Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1062.69+fips1
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Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-134.134+fips1
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Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1063.69+fips1
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Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.17.0-40.40
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Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.17.0-1019.19
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.17.0-1020.22
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Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.17.0-1018.18
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Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.17.0-1021.21
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Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.17.0-1017.19
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Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 6.17.0-40.40.1

Event History

May 8, 2026

CVE Published

via OSV·03:16 PM

Data Sourced

via OSV·03:16 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which Ubuntu kernel package families are listed as affected?

The listed package families are ubuntu/linux, ubuntu/linux-fips, ubuntu/linux-aws, ubuntu/linux-azure, ubuntu/linux-aws-fips, ubuntu/linux-azure-fips, ubuntu/linux-gcp, and ubuntu/linux-gcp-fips.

What condition is relevant to exploiting this issue?

The issue concerns timing attacks against TCP MD5 MAC comparison. Exploitation would rely on observing timing differences produced by a non-constant-time MAC comparison.

What is the remediation described for this vulnerability?

The resolved fix changes TCP MD5 MAC comparison to use an appropriate constant-time comparison helper function.

UBUNTU-CVE-2026-43383: Medium severity ubuntu/linux vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Which Ubuntu kernel package families are listed as affected?

What condition is relevant to exploiting this issue?

What is the remediation described for this vulnerability?

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