bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80738
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-03 13:06:12 UTC
Updated2026-09-04 05:17:14 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: bpf: Check sk_state before sk_protocol in bpf_tcp_*_syncookie bpf_tcp_gen_syncookie and bpf_tcp_check_syncookie accept a socket pointer 'sk' with argument type ARG_PTR_TO_BTF_ID_SOCK_COMMON. However, they access sk->sk_protocol without validating whether 'sk' represents a full socket. Fix this issue by checking sk->sk_state != TCP_LISTEN before inspecting sk->sk_protocol in both bpf_tcp_gen_syncookie and bpf_tcp_check_syncookie. Since mini-sockets are never in the TCP_LISTEN state, the condition short-circuits and prevents dereferencing fullsock-specific fields.

Risk And Classification

Primary CVSS: v3.1 7.3 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:L

EPSS: 0.001180000 probability, percentile 0.019120000 (date 2026-09-05)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
3.1CNADECLARED7.3HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 399040847084a69f345e0a52fd62f04654e0fce3 23f682083aa3fbc0c49667818efd6979a8bc5ac2 git Not specified
CNA Linux Linux affected 399040847084a69f345e0a52fd62f04654e0fce3 31a420a822ff92e2090bd5d65efe8e34e2d6d9b8 git Not specified
CNA Linux Linux affected 5.2 Not specified
CNA Linux Linux unaffected 5.2 semver Not specified
CNA Linux Linux unaffected 7.1.9 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/23f682083aa3fbc0c49667818efd6979a8bc5ac2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/31a420a822ff92e2090bd5d65efe8e34e2d6d9b8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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