CVE-2026-23439: udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n

Q: What is the severity of CVE-2026-23439?

The severity of CVE-2026-23439 is classified as medium with a CVSS score of 5.5.

Q: What kind of vulnerability is associated with CVE-2026-23439?

CVE-2026-23439 is categorized as a Null Pointer Dereference vulnerability in the Linux kernel.

Q: How can I mitigate CVE-2026-23439?

Mitigating CVE-2026-23439 involves ensuring that CONFIG_IPV6 is enabled in the Linux kernel configuration.

Q: What systems are affected by CVE-2026-23439?

CVE-2026-23439 affects the Linux kernel builds where CONFIG_IPV6 is disabled.

Q: What impact does CVE-2026-23439 have on Linux kernel functionality?

CVE-2026-23439 can lead to a NULL dereference and potential denial of service when certain UDP tunnel functionalities are invoked.

Published Apr 3, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

udptunnel: fix NULL deref caused by udpsockcreate6 when CONFIGIPV6=n

When CONFIGIPV6 is disabled, the udpsockcreate6() function returns 0 (success) without actually creating a socket. Callers such as foucreate() then proceed to dereference the uninitialized socket pointer, resulting in a NULL pointer dereference.

The captured NULL deref crash: BUG: kernel NULL pointer dereference, address: 0000000000000018 RIP: 0010:founladddoit (net/ipv4/foucore.c:590 net/ipv4/foucore.c:764) [...] Call Trace: <TASK> genlfamilyrcvmsgdoit.constprop.0 (net/netlink/genetlink.c:1114) genlrcvmsg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209) [...] netlinkrcvskb (net/netlink/afnetlink.c:2550) genlrcv (net/netlink/genetlink.c:1219) netlinkunicast (net/netlink/afnetlink.c:1319 net/netlink/afnetlink.c:1344) netlinksendmsg (net/netlink/afnetlink.c:1894) socksendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1)) syssendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1)) x64syssendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1)) dosyscall64 (arch/x86/entry/syscall64.c:63 (discriminator 1) arch/x86/entry/syscall64.c:94 (discriminator 1)) entrySYSCALL64afterhwframe (net/arch/x86/entry/entry64.S:130)

This patch makes udpsockcreate6 return -EPFNOSUPPORT instead, so callers correctly take their error paths. There is only one caller of the vulnerable function and only privileged users can trigger it.

Affected Software

264 affected componentsFixes available

Linux Linux kernel

Linux Linux kernel>=3.18.1<5.10.253

Linux Linux kernel>=5.11<5.15.203

Linux Linux kernel>=5.16<6.1.167

Linux Linux kernel>=6.2<6.6.130

Linux Linux kernel>=6.7<6.12.78

Linux Linux kernel>=6.13<6.18.20

Linux Linux kernel>=6.19<6.19.10

Linux Linux kernel=3.18

Linux Linux kernel=7.0-rc1

Linux Linux kernel=7.0-rc2

Linux Linux kernel=7.0-rc3

Linux Linux kernel=7.0-rc4

Linux Linux kernel=7.0-rc5

Linux Linux kernel=7.0-rc6

Linux Linux kernel=7.0-rc7

debian/linux

6.1.176-16.1.190-16.12.107-16.12.115-27.2.12-17.2.15-1

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-lts-xenial*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-hwe*

ubuntu/linux-azure*

ubuntu/linux-gcp*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-kvm*

ubuntu/linux-oracle*

ubuntu/linux-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-aws-5.4*

ubuntu/linux-azure*

ubuntu/linux-azure-4.15*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-5.4*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-4.15*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gcp-5.4*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-5.4*

ubuntu/linux-hwe-edge*

ubuntu/linux-ibm-5.4*

ubuntu/linux-kvm*

ubuntu/linux-oem*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-oracle-5.4*

ubuntu/linux-raspi-5.4*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.15<5.15.0-1112.119~20.04.1

5.15.0-1112.119~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1117.126~20.04.1

5.15.0-1117.126~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1117.126~20.04.2

5.15.0-1117.126~20.04.2

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1112.122~20.04.1

5.15.0-1112.122~20.04.1

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<5.15.0-186.196~20.04.1

5.15.0-186.196~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1106.110~20.04.1

5.15.0-1106.110~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1107.113~20.04.1

5.15.0-1107.113~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-184.194~20.04.1

5.15.0-184.194~20.04.1

ubuntu/linux-nvidia-tegra-5.15<5.15.0-1064.66~20.04.1

5.15.0-1064.66~20.04.1

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.15<5.15.0-1109.115~20.04.1

5.15.0-1109.115~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1106.110~20.04.1

5.15.0-1106.110~20.04.1

ubuntu/linux-riscv-5.8*

ubuntu/linux-xilinx-zynqmp*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<5.15.0-186.196

5.15.0-186.196

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1112.119

5.15.0-1112.119

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1061.64~22.04.1

6.8.0-1061.64~22.04.1

ubuntu/linux-azure<5.15.0-1117.126

5.15.0-1117.126

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<5.15.0-1117.126

5.15.0-1117.126

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<5.15.0-1112.122

5.15.0-1112.122

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1064.72~22.04.1

6.8.0-1064.72~22.04.1

ubuntu/linux-gke<5.15.0-1108.114

5.15.0-1108.114

ubuntu/linux-gkeop<5.15.0-1095.103

5.15.0-1095.103

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<5.15.0-1106.110

5.15.0-1106.110

ubuntu/linux-ibm-6.8<6.8.0-1061.62~22.04.1

6.8.0-1061.62~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1107.113

5.15.0-1107.113

ubuntu/linux-kvm<5.15.0-1104.109

5.15.0-1104.109

ubuntu/linux-lowlatency<5.15.0-184.194

5.15.0-184.194

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-136.136.2~22.04.1

6.8.0-136.136.2~22.04.1

ubuntu/linux-nvidia<5.15.0-1107.108

5.15.0-1107.108

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1059.62~22.04.1

6.8.0-1059.62~22.04.1

ubuntu/linux-nvidia-tegra<5.15.0-1064.66

5.15.0-1064.66

ubuntu/linux-nvidia-tegra-igx<5.15.0-1053.53

5.15.0-1053.53

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1109.115

5.15.0-1109.115

ubuntu/linux-oracle-6.5*

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

6.8.0-1058.61~22.04.1

ubuntu/linux-raspi<5.15.0-1106.109

5.15.0-1106.109

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-136.136~22.04.3

6.8.0-136.136~22.04.3

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1075.79

5.15.0-1075.79

ubuntu/linux-bluefield<5.15.0-1096.98

5.15.0-1096.98

ubuntu/linux-intel-iot-realtime<5.15.0-1104.106

5.15.0-1104.106

ubuntu/linux-realtime<5.15.0-1111.120

5.15.0-1111.120

ubuntu/linux-realtime-6.8<6.8.1-1056.57~22.04.2

6.8.1-1056.57~22.04.2

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1112.119+fips1

5.15.0-1112.119+fips1

ubuntu/linux-azure-fips<5.15.0-1117.126+fips1

5.15.0-1117.126+fips1

ubuntu/linux-fips<5.15.0-186.196+fips1

5.15.0-186.196+fips1

ubuntu/linux-gcp-fips<5.15.0-1112.122+fips1

5.15.0-1112.122+fips1

ubuntu/linux<6.8.0-136.136

6.8.0-136.136

ubuntu/linux-aws<6.8.0-1061.64

6.8.0-1061.64

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

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*

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<6.8.0-1064.72

6.8.0-1064.72

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gke<6.8.0-1059.67

6.8.0-1059.67

ubuntu/linux-gkeop<6.8.0-1046.50

6.8.0-1046.50

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-ibm<6.8.0-1061.62

6.8.0-1061.62

ubuntu/linux-lowlatency<6.8.0-136.136.2

6.8.0-136.136.2

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1059.62

6.8.0-1059.62

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-lowlatency<6.8.0-1059.62.1

6.8.0-1059.62.1

ubuntu/linux-nvidia-tegra<6.8.0-1030.31

6.8.0-1030.31

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1058.61

6.8.0-1058.61

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-raspi<6.8.0-1061.65

6.8.0-1061.65

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-xilinx<6.8.0-1033.34

6.8.0-1033.34

ubuntu/linux-bluefield<6.8.0-1028.33

6.8.0-1028.33

ubuntu/linux-raspi-realtime<6.8.0-2050.52

6.8.0-2050.52

ubuntu/linux-realtime<6.8.1-1056.57

6.8.1-1056.57

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1061.64+fips1

6.8.0-1061.64+fips1

ubuntu/linux-azure-fips<6.8.0-1063.71+fips2

6.8.0-1063.71+fips2

ubuntu/linux-fips<6.8.0-136.136+fips2

6.8.0-136.136+fips2

ubuntu/linux-gcp-fips<6.8.0-1064.72+fips1

6.8.0-1064.72+fips1

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp*

ubuntu/linux-oracle*

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

linux/kernel>=3.18.0<5.10.253

5.10.253

linux/kernel>=5.11.0<5.15.203

5.15.203

linux/kernel>=5.16.0<6.1.167

6.1.167

linux/kernel>=6.2.0<6.6.130

6.6.130

linux/kernel>=6.7.0<6.12.78

6.12.78

linux/kernel>=6.13.0<6.18.20

6.18.20

linux/kernel>=6.19.0<6.19.10

6.19.10

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1
Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.119~20.04.1
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Upgrade ubuntu/linux-azure-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.126~20.04.1
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Fixed in 5.15.0-1117.126~20.04.2
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Fixed in 5.15.0-1112.122~20.04.1
Upgrade
Upgrade ubuntu/linux-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-186.196~20.04.1
Upgrade
Upgrade ubuntu/linux-ibm-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.110~20.04.1
Upgrade
Upgrade ubuntu/linux-intel-iotg-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1107.113~20.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-184.194~20.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1064.66~20.04.1
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Upgrade ubuntu/linux-oracle-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1109.115~20.04.1
Upgrade
Upgrade ubuntu/linux-riscv-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1106.110~20.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 5.15.0-186.196
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.119
Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1061.64~22.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.126
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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
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.126
Upgrade
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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Fixed in 5.15.0-1112.122
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Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1064.72~22.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 5.15.0-1108.114
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 5.15.0-1095.103
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Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-136.136~22.04.1
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Fixed in 5.15.0-1106.110
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1061.62~22.04.1
Upgrade
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Fixed in 5.15.0-1107.113
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Fixed in 5.15.0-1104.109
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Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 5.15.0-184.194
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Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-136.136.2~22.04.1
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Fixed in 5.15.0-1107.108
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Fixed in 6.8.0-1059.62~22.04.1
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Fixed in 5.15.0-1064.66
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Fixed in 5.15.0-1053.53
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Fixed in 5.15.0-1109.115
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Fixed in 6.8.0-1058.61~22.04.1
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Fixed in 5.15.0-1106.109
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Fixed in 6.8.0-136.136~22.04.3
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Fixed in 5.15.0-1075.79
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Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 5.15.0-1096.98
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Fixed in 5.15.0-1104.106
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 5.15.0-1111.120
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1056.57~22.04.2
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.119+fips1
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Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.126+fips1
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Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-186.196+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 5.15.0-1112.122+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-136.136
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Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1061.64
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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-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1062.69
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Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1064.72
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Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1059.67
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Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.50
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Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1061.62
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Fixed in 6.8.0-136.136.2
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Fixed in 6.8.0-1059.62
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Fixed in 6.8.0-1059.62.1
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Fixed in 6.8.0-1030.31
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Fixed in 6.8.0-1058.61
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Fixed in 6.8.0-1061.65
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Fixed in 6.8.0-1033.34
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Fixed in 6.8.0-1028.33
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Fixed in 6.8.0-2050.52
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Fixed in 6.8.1-1056.57
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Fixed in 6.8.0-1061.64+fips1
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Fixed in 6.8.0-1063.71+fips2
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Fixed in 6.8.0-136.136+fips2
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Fixed in 6.8.0-1064.72+fips1
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Fixed in 5.10.253
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Fixed in 5.15.203
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Fixed in 6.1.167
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Fixed in 6.6.130
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Fixed in 6.12.78
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Fixed in 6.18.20
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Fixed in 6.19.10

Event History

Apr 3, 2026

CVE Published

via MITRE·03:15 PM

Data Sourced

via MITRE·03:15 PM

Description

Data Sourced

via OSV·03:15 PM

DescriptionAffected Software

Data Sourced

via OSV·04:16 PM

Severity

Data Sourced

via NVD·04:16 PM

RemedyDescriptionSeverityWeaknessAffected Software

Apr 25, 2026

Data Sourced

via Microsoft·08:05 AM

DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

What is the severity of CVE-2026-23439?

The severity of CVE-2026-23439 is classified as medium with a CVSS score of 5.5.

What kind of vulnerability is associated with CVE-2026-23439?

CVE-2026-23439 is categorized as a Null Pointer Dereference vulnerability in the Linux kernel.

How can I mitigate CVE-2026-23439?

Mitigating CVE-2026-23439 involves ensuring that CONFIG_IPV6 is enabled in the Linux kernel configuration.

What systems are affected by CVE-2026-23439?

CVE-2026-23439 affects the Linux kernel builds where CONFIG_IPV6 is disabled.

What impact does CVE-2026-23439 have on Linux kernel functionality?

CVE-2026-23439 can lead to a NULL dereference and potential denial of service when certain UDP tunnel functionalities are invoked.

CVE-2026-23439: udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n

Affected Software

Remediation

Event History

Parent advisories

Peer vulnerabilities

Frequently Asked Questions

What is the severity of CVE-2026-23439?

What kind of vulnerability is associated with CVE-2026-23439?

How can I mitigate CVE-2026-23439?

What systems are affected by CVE-2026-23439?

What impact does CVE-2026-23439 have on Linux kernel functionality?

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