CVE-2026-80634

CVE CVE-2026-80634EUVD EUVD-2026-67510Published 2026-08-28T06:48:49.000ZLast changed 2026-08-29T06:21:33.000ZCVSS 9.8

What the advisory describes

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 ].

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux 5.13; e990cef6516daa4e1e236433579e333f74fd38cb <e052f920773b73be49eb4d8702a9f85de7464363; patch: 0; e990cef6516daa4e1e236433579e333f74fd38cb <2f55fa28011c97d6495d5787808db10a8c2d690d; patch: 7.1.5; patch: 7.2

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

Linux — Linux

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