CVE-2026-63956: USB: serial: cypress_m8: fix memory corruption with small endpoint

Q: Who is exposed to this issue?

Systems running an affected Linux kernel are exposed when the cypress_m8 USB serial driver interacts with a malicious USB device that reports an interrupt-out endpoint maximum packet size smaller than eight bytes.

Q: What does an attacker need to exploit it?

An attacker needs local access sufficient to present or connect a malicious USB device. The device must advertise a too-small interrupt-out endpoint packet size.

Q: What could exploitation cause?

The malformed endpoint size can cause user-controlled slab memory corruption or a NULL-pointer dereference. The reported impact includes compromise of confidentiality, integrity, and availability.

Q: What mitigation is available if patching cannot happen immediately?

Avoid connecting untrusted USB devices that could present as Cypress M8 USB serial hardware. The provided data does not identify another configuration-based mitigation.

Published Jul 19, 2026

Updated

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

USB: serial: cypressm8: fix memory corruption with small endpoint

Make sure that the interrupt-out endpoint max packet size is at least eight bytes to avoid user-controlled slab corruption or NULL-pointer dereference should a malicious device report a smaller size.

Affected Software

277 affected componentsFixes available

Linux Linux kernel

Linux Linux kernel>=2.6.26<5.10.259

Linux Linux kernel>=5.11<5.15.210

Linux Linux kernel>=5.16<6.1.176

Linux Linux kernel>=6.2<6.6.143

Linux Linux kernel>=6.7<6.12.93

Linux Linux kernel>=6.13<6.18.35

Linux Linux kernel>=6.19<7.0.12

Linux Linux kernel=7.1-rc1

Linux Linux kernel=7.1-rc2

Linux Linux kernel=7.1-rc3

Linux Linux kernel=7.1-rc4

Linux Linux kernel=7.1-rc5

ubuntu/linux*

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<5.15.0-1117.124~20.04.1

5.15.0-1117.124~20.04.1

ubuntu/linux-aws-5.8*

ubuntu/linux-azure*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.15<5.15.0-1123.132~20.04.1

5.15.0-1123.132~20.04.1

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-5.15<5.15.0-1122.131~20.04.1

5.15.0-1122.131~20.04.1

ubuntu/linux-bluefield*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.15<5.15.0-1118.128~20.04.1

5.15.0-1118.128~20.04.1

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<5.15.0-198.208~20.04.1

5.15.0-198.208~20.04.1

ubuntu/linux-hwe-5.8*

ubuntu/linux-ibm*

ubuntu/linux-ibm-5.15<5.15.0-1111.115~20.04.1

5.15.0-1111.115~20.04.1

ubuntu/linux-intel-5.13*

ubuntu/linux-intel-iotg-5.15<5.15.0-1112.118~20.04.1

5.15.0-1112.118~20.04.1

ubuntu/linux-iot*

ubuntu/linux-kvm*

ubuntu/linux-lowlatency-hwe-5.15<5.15.0-195.205~20.04.1

5.15.0-195.205~20.04.1

ubuntu/linux-nvidia-tegra-5.15*

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<5.15.0-1114.120~20.04.1

5.15.0-1114.120~20.04.1

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.15<5.15.0-1111.115~20.04.1

5.15.0-1111.115~20.04.1

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<5.15.0-198.208

5.15.0-198.208

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws<5.15.0-1117.124

5.15.0-1117.124

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1066.69~22.04.1

6.8.0-1066.69~22.04.1

ubuntu/linux-azure<5.15.0-1123.132

5.15.0-1123.132

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1070.78~22.04.1

6.8.0-1070.78~22.04.1

ubuntu/linux-azure-fde<5.15.0-1122.131

5.15.0-1122.131

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1068.75~22.04.1

6.8.0-1068.75~22.04.1

ubuntu/linux-gcp<5.15.0-1118.128

5.15.0-1118.128

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1070.78~22.04.1

6.8.0-1070.78~22.04.1

ubuntu/linux-gke<5.15.0-1113.119

5.15.0-1113.119

ubuntu/linux-gkeop<5.15.0-1100.108

5.15.0-1100.108

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm<5.15.0-1111.115

5.15.0-1111.115

ubuntu/linux-ibm-6.8<6.8.0-1066.67~22.04.1

6.8.0-1066.67~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-intel-iotg<5.15.0-1112.118

5.15.0-1112.118

ubuntu/linux-kvm<5.15.0-1109.114

5.15.0-1109.114

ubuntu/linux-lowlatency<5.15.0-195.205

5.15.0-195.205

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-146.146.1~22.04.1

6.8.0-146.146.1~22.04.1

ubuntu/linux-nvidia<5.15.0-1112.113

5.15.0-1112.113

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1064.67~22.04.1

6.8.0-1064.67~22.04.1

ubuntu/linux-nvidia-tegra*

ubuntu/linux-nvidia-tegra-igx*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle<5.15.0-1114.120

5.15.0-1114.120

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8*

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-146.146~22.04.1

6.8.0-146.146~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-xilinx-zynqmp<5.15.0-1080.84

5.15.0-1080.84

ubuntu/linux-bluefield<5.15.0-1101.103

5.15.0-1101.103

ubuntu/linux-intel-iot-realtime<5.15.0-1109.111

5.15.0-1109.111

ubuntu/linux-realtime<5.15.0-1116.125

5.15.0-1116.125

ubuntu/linux-realtime-6.8<6.8.1-1061.62~22.04.1

6.8.1-1061.62~22.04.1

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux-aws-fips<5.15.0-1117.124+fips1

5.15.0-1117.124+fips1

ubuntu/linux-azure-fips<5.15.0-1123.132+fips1

5.15.0-1123.132+fips1

ubuntu/linux-fips<5.15.0-198.208+fips1

5.15.0-198.208+fips1

ubuntu/linux-gcp-fips<5.15.0-1118.128+fips1

5.15.0-1118.128+fips1

ubuntu/linux<6.8.0-146.146

6.8.0-146.146

ubuntu/linux-aws<6.8.0-1066.69

6.8.0-1066.69

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-azure<6.8.0-1070.78

6.8.0-1070.78

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0<7.0.0-1014.14~24.04.1

7.0.0-1014.14~24.04.1

ubuntu/linux-azure-fde<6.8.0-1068.75

6.8.0-1068.75

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1013.13~24.04.1

7.0.0-1013.13~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1070.78

6.8.0-1070.78

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1011.11~24.04.1

7.0.0-1011.11~24.04.1

ubuntu/linux-gke<6.8.0-1065.73

6.8.0-1065.73

ubuntu/linux-gkeop<6.8.0-1051.55

6.8.0-1051.55

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-28.28~24.04.1

7.0.0-28.28~24.04.1

ubuntu/linux-ibm<6.8.0-1066.67

6.8.0-1066.67

ubuntu/linux-lowlatency<6.8.0-146.146.1

6.8.0-146.146.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1064.67

6.8.0-1064.67

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0<7.0.0-1016.16~24.04.1

7.0.0-1016.16~24.04.1

ubuntu/linux-nvidia-lowlatency<6.8.0-1064.67.1

6.8.0-1064.67.1

ubuntu/linux-nvidia-tegra*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1063.66

6.8.0-1063.66

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1011.11~24.04.1

7.0.0-1011.11~24.04.1

ubuntu/linux-raspi*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-riscv-7.0<7.0.0-28.28.1~24.04.3

7.0.0-28.28.1~24.04.3

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1032.37

6.8.0-1032.37

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime<6.8.1-1061.62

6.8.1-1061.62

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1066.69+fips1

6.8.0-1066.69+fips1

ubuntu/linux-azure-fips<6.8.0-1069.77+fips1

6.8.0-1069.77+fips1

ubuntu/linux-fips<6.8.0-146.146+fips1

6.8.0-146.146+fips1

ubuntu/linux-gcp-fips<6.8.0-1070.78+fips1

6.8.0-1070.78+fips1

ubuntu/linux<7.0.0-28.28

7.0.0-28.28

ubuntu/linux-aws<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-azure<7.0.0-1010.10

7.0.0-1010.10

ubuntu/linux-azure-fde<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-gcp<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-gke<7.0.0-1003.4

7.0.0-1003.4

ubuntu/linux-ibm<7.0.0-1010.10

7.0.0-1010.10

ubuntu/linux-nvidia<7.0.0-1016.16

7.0.0-1016.16

ubuntu/linux-nvidia-bos<7.0.0-2016.16

7.0.0-2016.16

ubuntu/linux-oem-7.0<7.0.0-1009.9

7.0.0-1009.9

ubuntu/linux-oracle<7.0.0-1008.8

7.0.0-1008.8

ubuntu/linux-raspi<7.0.0-1015.15

7.0.0-1015.15

ubuntu/linux-realtime<7.0.0-28.28.1

7.0.0-28.28.1

ubuntu/linux-riscv<7.0.0-28.28.1

7.0.0-28.28.1

debian/linux<6.1.176-1

6.1.176-1

debian/linux<6.12.94-1

6.12.94-1

debian/linux<7.0.12-1

7.0.12-1

linux/kernel>=2.6.26<5.10.259

5.10.259

linux/kernel>=5.11.0<5.15.210

5.15.210

linux/kernel>=5.16.0<6.1.176

6.1.176

linux/kernel>=6.2.0<6.6.143

6.6.143

linux/kernel>=6.7.0<6.12.93

6.12.93

linux/kernel>=6.13.0<6.18.35

6.18.35

linux/kernel>=6.19.0<7.0.12

7.0.12

debian/linux

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

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-5.15 to a version that resolves this vulnerability.
Fixed in 5.15.0-1117.124~20.04.1
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Fixed in 5.15.0-1123.132~20.04.1
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Fixed in 5.15.0-1122.131~20.04.1
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Fixed in 5.15.0-1118.128~20.04.1
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Fixed in 5.15.0-198.208~20.04.1
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Fixed in 5.15.0-1111.115~20.04.1
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Fixed in 5.15.0-1112.118~20.04.1
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Fixed in 5.15.0-195.205~20.04.1
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Fixed in 5.15.0-1114.120~20.04.1
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Fixed in 5.15.0-1111.115~20.04.1
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Fixed in 5.15.0-198.208
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Fixed in 5.15.0-1117.124
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Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1066.69~22.04.1
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Fixed in 5.15.0-1123.132
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Fixed in 6.8.0-1070.78~22.04.1
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Fixed in 5.15.0-1122.131
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Fixed in 6.8.0-1068.75~22.04.1
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Fixed in 5.15.0-1118.128
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Fixed in 6.8.0-1070.78~22.04.1
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Fixed in 5.15.0-1113.119
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Fixed in 5.15.0-1100.108
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Fixed in 5.15.0-1111.115
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Fixed in 6.8.0-1066.67~22.04.1
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Fixed in 5.15.0-1112.118
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Fixed in 5.15.0-1109.114
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Fixed in 5.15.0-195.205
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Fixed in 6.8.0-146.146.1~22.04.1
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Fixed in 5.15.0-1112.113
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Fixed in 6.8.0-1064.67~22.04.1
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Fixed in 5.15.0-1114.120
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Fixed in 6.8.0-146.146~22.04.1
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Fixed in 5.15.0-1080.84
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Fixed in 5.15.0-1101.103
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Fixed in 5.15.0-1109.111
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Fixed in 5.15.0-1116.125
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Fixed in 6.8.1-1061.62~22.04.1
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Fixed in 5.15.0-1117.124+fips1
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Fixed in 5.15.0-1123.132+fips1
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Fixed in 5.15.0-198.208+fips1
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Fixed in 5.15.0-1118.128+fips1
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Fixed in 6.8.0-146.146
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Fixed in 6.8.0-1066.69
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Fixed in 6.8.0-1070.78
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Upgrade ubuntu/linux-azure-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14~24.04.1
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Fixed in 6.8.0-1068.75
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Fixed in 7.0.0-1013.13~24.04.1
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Fixed in 6.8.0-1070.78
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Fixed in 7.0.0-1011.11~24.04.1
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Fixed in 6.8.0-1065.73
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Fixed in 6.8.0-1051.55
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Fixed in 7.0.0-28.28~24.04.1
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Fixed in 6.8.0-1066.67
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Fixed in 6.8.0-146.146.1
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Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1064.67
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Upgrade ubuntu/linux-nvidia-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.16~24.04.1
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Fixed in 6.8.0-1064.67.1
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Fixed in 6.8.0-1063.66
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Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1011.11~24.04.1
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Fixed in 7.0.0-28.28.1~24.04.3
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Fixed in 6.8.0-1032.37
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Fixed in 6.8.1-1061.62
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Fixed in 6.8.0-1066.69+fips1
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Fixed in 6.8.0-1069.77+fips1
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Fixed in 6.8.0-146.146+fips1
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Fixed in 6.8.0-1070.78+fips1
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Fixed in 7.0.0-28.28
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Fixed in 7.0.0-1009.9
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Fixed in 7.0.0-1010.10
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Fixed in 7.0.0-1009.9
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Fixed in 7.0.0-1008.8
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Fixed in 7.0.0-1003.4
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Fixed in 7.0.0-1010.10
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Fixed in 7.0.0-1016.16
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Fixed in 7.0.0-2016.16
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Fixed in 7.0.0-1009.9
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Fixed in 7.0.0-1008.8
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Fixed in 7.0.0-1015.15
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Fixed in 7.0.0-28.28.1
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Fixed in 7.0.0-28.28.1
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Fixed in 6.1.176-1
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Fixed in 6.12.94-1
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Fixed in 7.0.12-1
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Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.14-1
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Fixed in 5.10.259
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Fixed in 5.15.210
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Fixed in 6.1.176
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Fixed in 6.6.143
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Fixed in 6.12.93
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Fixed in 6.18.35
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Fixed in 7.0.12
Compensating control
Ensure the USB serial cypress_m8 interrupt-out endpoint maximum packet size is at least eight bytes; reject or otherwise prevent use of endpoints reporting a smaller size.

Event History

Jul 19, 2026

CVE Published

via MITRE·02:55 PM

Data Sourced

via MITRE·02:55 PM

Description

Data Sourced

via OSV·02:55 PM

DescriptionAffected Software

Data Sourced

via NVD·04:17 PM

RemedyDescriptionSeverityWeaknessAffected Software

Data Sourced

via OSV·04:17 PM

Severity

Frequently Asked Questions

Who is exposed to this issue?

Systems running an affected Linux kernel are exposed when the cypress_m8 USB serial driver interacts with a malicious USB device that reports an interrupt-out endpoint maximum packet size smaller than eight bytes.

What does an attacker need to exploit it?

An attacker needs local access sufficient to present or connect a malicious USB device. The device must advertise a too-small interrupt-out endpoint packet size.

What could exploitation cause?

The malformed endpoint size can cause user-controlled slab memory corruption or a NULL-pointer dereference. The reported impact includes compromise of confidentiality, integrity, and availability.

What mitigation is available if patching cannot happen immediately?

Avoid connecting untrusted USB devices that could present as Cypress M8 USB serial hardware. The provided data does not identify another configuration-based mitigation.

CVE-2026-63956: USB: serial: cypress_m8: fix memory corruption with small endpoint

Affected Software

Remediation

Event History

Frequently Asked Questions

Who is exposed to this issue?

What does an attacker need to exploit it?

What could exploitation cause?

What mitigation is available if patching cannot happen immediately?

Company

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