Description
In the Linux kernel, the following vulnerability has been resolved:
netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag
The DEV_PATH_BR_VLAN_UNTAG case post-decrements info->num_encaps
inside WARN_ON_ONCE(). num_encaps is u8, so if it's already 0 the
decrement still happens and wraps it to 255. The break only leaves
the inner switch -- a later path entry can set info->indev back to
a real device, and we end up returning with num_encaps == 255.
nft_dev_forward_path() then walks info.encap[] (size 2) up to
num_encaps, which means an OOB stack read and a bogus count copied
into the route descriptor.
Should only happen on a malformed bridge path stack, hence the WARN,
but worth handling sanely. Move the decrement out of the WARN.
[ While at this, remove the WARN_ON_ONCE since this can only happen
with a buggy bridge path stack --pablo ].
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.13 | 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 | 7.1.5-1 | — |
| 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 | 7.0.0-38.38 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-aws +1 | 7.0.0-1014.14 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-azure | 7.0.0-1017.17 | USN-8888-1 |
| Ubuntu 26.04 LTS | linux-azure-fde | 7.0.0-1016.16 | USN-8888-1 |
| Ubuntu 26.04 LTS | linux-gke | 7.0.0-1008.9 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-ibm +1 | 7.0.0-1015.15 | USN-8889-1, USN-8887-1 |
| Ubuntu 26.04 LTS | linux-nvidia | 7.0.0-1025.26 | USN-9043-1 |
| Ubuntu 26.04 LTS | linux-nvidia-bos | 7.0.0-2022.23 | USN-9003-1 |
| Ubuntu 26.04 LTS | linux-oracle | 7.0.0-1013.13 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-raspi | 7.0.0-1023.23 | USN-9021-1 |
| Ubuntu 26.04 LTS | linux-riscv +1 | 7.0.0-38.38.1 | USN-8887-1 |
| Ubuntu 24.04 LTS | linux +43 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-aws-7.0 +1 | 7.0.0-1014.14~24.04.1 | USN-8887-3, USN-8887-2 |
| Ubuntu 24.04 LTS | linux-azure-7.0 | 7.0.0-1017.17~24.04.1 | USN-8888-2 |
| Ubuntu 24.04 LTS | linux-azure-fde-7.0 | 7.0.0-1016.16~24.04.1 | USN-8888-2 |
| Ubuntu 24.04 LTS | linux-hwe-7.0 | 7.0.0-38.38~24.04.4 | USN-8887-3 |
| Ubuntu 24.04 LTS | linux-nvidia-7.0 | 7.0.0-1024.25~24.04.1 | USN-9003-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1038.42 | USN-9002-1 |
| Ubuntu 24.04 LTS | linux-oracle-7.0 | 7.0.0-1013.13~24.04.1 | USN-8887-3 |
| Ubuntu 24.04 LTS | linux-riscv-7.0 | 7.0.0-38.38.1~24.04.1 | — |
| Ubuntu 22.04 LTS | linux +59 | No fix yet | — |
Show 9 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-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-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 +10 | No fix yet | — |
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 12
- USN-8887-1 linux, linux-aws, linux-gcp, linux-gke, linux-ibm, linux-oracle, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-9021-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8888-2 linux-azure-7.0, linux-azure-fde-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-9003-1 linux-nvidia-7.0, linux-nvidia-bos vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8889-1 linux-oem-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8887-3 linux-gcp-7.0, linux-hwe-7.0, linux-oracle-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-9043-1 linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8888-1 linux-azure, linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-9002-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- USN-8887-2 linux-aws-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 13, 2026
- WID-SEC-2026-3075 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- ALAS2023-2026-3402 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 11, 2026
References
- https://git.kernel.org/stable/c/9a4e3a9017ba3da2de187b72ed6545641a0d0a84
- https://git.kernel.org/stable/c/1b52aeb40c9f04bf50eeb4ea09142139d163e239
- https://git.kernel.org/stable/c/ee8440bb000fff4ef8acbfc99652851e9ca0a35b
- https://git.kernel.org/stable/c/547ea9f567498e4accc89e7816264f15a1a0629f
- https://git.kernel.org/stable/c/2f55fa28011c97d6495d5787808db10a8c2d690d
- https://git.kernel.org/stable/c/e052f920773b73be49eb4d8702a9f85de7464363