Description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_u32: validate offshift to prevent shift-out-of-bounds
u32_change() copies the user-provided tc_u32_sel.offshift (unsigned char,
0-255) into the kernel knode object without bounds validation. When a
packet later hits u32_classify() with TC_U32_VAROFFSET set, it evaluates
`ntohs(offmask & *data) >> offshift` where the left operand is a 16-bit
value promoted to a 32-bit int. Any offshift >= 32 is undefined behavior
per C11 6.5.7p3, triggerable by an unprivileged user via user/network
namespaces.
UBSAN: shift-out-of-bounds in net/sched/cls_u32.c:236:43
shift exponent 32 is too large for 32-bit type int
Fix this by rejecting offshift >= 16 during filter creation in
u32_change().
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 2.6.12 | 6.1.191 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 7.1.8-1 | — |
| Debian 13 | linux | 6.12.115-2 | — |
| Debian 12 | linux | No fix yet | — |
| Debian 12 | linux-6.12 | 6.12.115-2~deb12u1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | No fix yet | — |
| Ubuntu 26.04 LTS | linux | 7.0.0-42.42 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-aws | 7.0.0-1016.17 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-azure | 7.0.0-1020.21 | USN-9019-1 |
| Ubuntu 26.04 LTS | linux-azure-fde | 7.0.0-1019.19 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-gcp | 7.0.0-1016.18 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-gke | 7.0.0-1010.11 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-ibm +1 | 7.0.0-1017.17 | USN-8960-1, USN-8959-1 |
| Ubuntu 26.04 LTS | linux-nvidia +1 | No fix yet | — |
| Ubuntu 26.04 LTS | linux-oracle | 7.0.0-1015.16 | USN-8959-1 |
| Ubuntu 26.04 LTS | linux-raspi | 7.0.0-1023.23 | USN-9021-1 |
| Ubuntu 26.04 LTS | linux-realtime | 7.0.0-43.43.1 | USN-9020-1 |
| Ubuntu 26.04 LTS | linux-riscv | 7.0.0-42.42.1 | — |
| Ubuntu 24.04 LTS | linux +45 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-aws-7.0 | 7.0.0-1017.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-azure-fde-7.0 | 7.0.0-1019.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-gcp-7.0 | 7.0.0-1017.19~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-hwe-7.0 | 7.0.0-42.42~24.04.1 | USN-8959-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1036.39 | USN-8886-1 |
| Ubuntu 24.04 LTS | linux-oracle-7.0 | 7.0.0-1016.18~24.04.1 | USN-9020-1 |
| Ubuntu 24.04 LTS | linux-riscv-7.0 | 7.0.0-42.42.1~24.04.1 | — |
| Ubuntu 22.04 LTS | linux +59 | No fix yet | — |
Show 18 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime +3 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime +2 | No fix yet | — |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 16.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +21 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux +12 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux +7 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux +3 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +5 | 6.4.0-150700.53.87.3 | SUSE-SU-2026:4935-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.87.3.150700.17.49.2 | SUSE-SU-2026:4935-1 |
| SLES 15 SP7 | kernel-obs-build | 6.4.0-150700.53.87.2 | SUSE-SU-2026:4935-1 |
| SLES 15 SP7 | kernel-syms | 6.4.0-150700.53.87.1 | SUSE-SU-2026:4935-1 |
| SLES 12 SP5 | kernel-syms +2 | 4.12.14-122.336.1 | SUSE-SU-2026:4892-1 |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.40.1 | SUSE-SU-2026:24446-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24446-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.40.1 | SUSE-SU-2026:24446-1, SUSE-SU-2026:24437-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24446-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | SUSE-SU-2026:24422-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.40.1 | SUSE-SU-2026:24422-1, SUSE-SU-2026:24386-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-159998.54.1.159998.21.39 | SUSE-SU-2026:24379-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-159998.54.1 | SUSE-SU-2026:24553-1, SUSE-SU-2026:24379-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-159998.54.1.159998.21.40 | SUSE-SU-2026:24371-1 |
| SLE Micro 6.0 | kernel-rt +4 | 6.4.0-159998.54.1 | SUSE-SU-2026:24473-1, SUSE-SU-2026:24371-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.87.3 | SUSE-SU-2026:4935-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_22 | 1-150700.1.3.1 | SUSE-SU-2026:4940-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_23 | 1-150700.15.3.2 | SUSE-SU-2026:4935-1 |
| SLE Live Patching 12 SP5 | kernel-default | 4.12.14-122.336.1 | SUSE-SU-2026:4892-1 |
| SLE Live Patching 12 SP5 | kgraft-patch-SLE12-SP5_Update_89 | 1-8.3.1 | SUSE-SU-2026:4892-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt +2 | 6.4.0-150700.7.81.1 | SUSE-SU-2026:4940-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.40.1.160000.2.29 | openSUSE-SU-2026:22167-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.40.1 | openSUSE-SU-2026:22167-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.114-139.210 | 1:1.0-0.amzn2023 | ALAS2023-2026-3402 |
| Amazon Linux 2023 | perf6.12 +11 | 1:6.12.114-139.210.amzn2023 | ALAS2023-2026-3402 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.161.1-1 | — |
Advisories 20
- USN-9021-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- WID-SEC-2026-2852 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-9020-1 linux-aws-7.0, linux-azure-fde, linux-azure-fde-7.0, linux-gcp-7.0, linux-gke, linux-oracle-7.0, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8959-1 linux, linux-aws, linux-gcp, linux-hwe-7.0, linux-ibm, linux-oracle vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9019-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8960-1 linux-oem-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8886-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- ALAS2023-2026-3402 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 11, 2026
- SUSE-SU-2026:24553-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 7, 2026
- SUSE-SU-2026:24473-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 4, 2026
- SUSE-SU-2026:24437-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:24446-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Nov 1, 2026
- SUSE-SU-2026:4940-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 31, 2026
- SUSE-SU-2026:4935-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 31, 2026
- SUSE-SU-2026:24422-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 30, 2026
- SUSE-SU-2026:24386-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 30, 2026
- SUSE-SU-2026:24379-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 27, 2026
- SUSE-SU-2026:24371-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 27, 2026
- openSUSE-SU-2026:22167-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 25, 2026
- SUSE-SU-2026:4892-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 24, 2026
References
- https://git.kernel.org/stable/c/7fd5b2287e5cf33e114fb7f0cef781a546039757
- https://git.kernel.org/stable/c/724c8edbacf1259988829cb9967f751222121d8a
- https://git.kernel.org/stable/c/006a4598da9a6b02e0ddc3ca5042b97224774364
- https://git.kernel.org/stable/c/9990cac513e8b191de2ee589051ea7ebf3cee940
- https://git.kernel.org/stable/c/313cb9ffc4101a885d791facf4b5ea3d5e06144d
- https://git.kernel.org/stable/c/aef96eead2860cbfa371e4471d4f04412213b958