CVE-2026-64531

CVE CVE-2026-64531EUVD EUVD-2026-49109Published 2026-07-27T06:32:32.000ZLast changed 2026-08-05T12:42:40.000ZCVSS 7.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure.

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 6.6.84 <6.6.145; patch: 7.1.5; patch: 5.15.212; 6b099d285d7ed324494b6d684f377aa103856118; a1e64addf3ff9257b45b78bc7d743781c3f41340 <3f1f755366687d051174739fb99f7d560202f60b; 6.13.8 <6.14; 6.12.20 <6.12.97; 6.14; patch: 7.2-rc4; 5.15.180 <5.15.212; a1e64addf3ff9257b45b78bc7d743781c3f41340 <dbd14f736be02cfe73049bd801af89becd1a0749; a1e64addf3ff9257b45b78bc7d743781c3f41340 <1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe; patch: 6.18.40; 2532adbfe917c0e71dba2650ffc6efe396314c87 <c66bd2626c2764f23764ff0f8277f44a9cfe8349; patch: 6.6.145; patch: 0; patch: 6.12.97; patch: 6.1.178; 057dbc5b72e9fcac439cd561c3a539b8a0edeb92 <ab855641241387db062a5e41d9ad6b8561542572; e6610f9c08b4c04cf7949c10fc246c071d00e935 <f1efff8858403191361a01269c6fe8dd7f55a385; 6.1.132 <6.1.178; 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485 <d573250d228401f707f4dbc09d11227a6215ee5f

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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