net: openvswitch: reject oversized nested action attrs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-64531
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-27 08:16:22 UTC
Updated2026-08-01 08:16:29 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001200000 probability, percentile 0.021640000 (date 2026-07-31)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 057dbc5b72e9fcac439cd561c3a539b8a0edeb92 ab855641241387db062a5e41d9ad6b8561542572 git Not specified
CNA Linux Linux affected 2532adbfe917c0e71dba2650ffc6efe396314c87 c66bd2626c2764f23764ff0f8277f44a9cfe8349 git Not specified
CNA Linux Linux affected 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485 d573250d228401f707f4dbc09d11227a6215ee5f git Not specified
CNA Linux Linux affected e6610f9c08b4c04cf7949c10fc246c071d00e935 f1efff8858403191361a01269c6fe8dd7f55a385 git Not specified
CNA Linux Linux affected a1e64addf3ff9257b45b78bc7d743781c3f41340 dbd14f736be02cfe73049bd801af89becd1a0749 git Not specified
CNA Linux Linux affected a1e64addf3ff9257b45b78bc7d743781c3f41340 1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe git Not specified
CNA Linux Linux affected a1e64addf3ff9257b45b78bc7d743781c3f41340 3f1f755366687d051174739fb99f7d560202f60b git Not specified
CNA Linux Linux affected 6b099d285d7ed324494b6d684f377aa103856118 git Not specified
CNA Linux Linux affected 5.15.180 5.15.212 semver Not specified
CNA Linux Linux affected 6.1.132 6.1.178 semver Not specified
CNA Linux Linux affected 6.6.84 6.6.145 semver Not specified
CNA Linux Linux affected 6.12.20 6.12.97 semver Not specified
CNA Linux Linux affected 6.13.8 6.14 semver Not specified
CNA Linux Linux affected 6.14 Not specified
CNA Linux Linux unaffected 6.14 semver Not specified
CNA Linux Linux unaffected 5.15.212 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc4 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
www.openwall.com/lists/oss-security/2026/08/01/3 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
www.openwall.com/lists/oss-security/2026/07/31/17 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
www.openwall.com/lists/oss-security/2026/08/01/1 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
www.openwall.com/lists/oss-security/2026/07/28/8 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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