seg6: validate SRH length before reading fixed fields

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72400
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:13 UTC
Updated2026-08-17 06:19:06 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: seg6: validate SRH length before reading fixed fields seg6_validate_srh() reads fixed SRH fields such as srh->type and srh->hdrlen before checking that the supplied length covers the fixed struct ipv6_sr_hdr fields. The BPF SEG6 encap path reaches this with a BPF program-supplied pointer and length: bpf_lwt_push_encap() and the SEG6 local BPF END_B6 and END_B6_ENCAP actions call bpf_push_seg6_encap(), which forwards the length to seg6_validate_srh() with no minimum-size guard. A 2-byte SEG6 encap header can therefore make the validator read srh->type at offset 2 beyond the caller-supplied buffer. Reject lengths shorter than the fixed SRH at the top of seg6_validate_srh(), before any field is read. This fixes the BPF helper path and keeps the common validator robust.

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: 0.001640000 probability, percentile 0.060880000 (date 2026-08-17)

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 fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 715eb12e453df752f1b4baaf972c3acff0ab9402 git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73 git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 804bb969f194c93497ba632b98343794c6367fdc git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 0fc7069d39239978130c37ebceaec85c8948d3f1 git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 8dba7a94a269b88e500aafc25ad567ef6a423698 git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 c9961336aa5ff83092f23e33ee86666a9dbd1b2a git Not specified
CNA Linux Linux affected fe94cc290f535709d3c5ebd1e472dfd0aec7ee79 a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa git Not specified
CNA Linux Linux affected 4.18 Not specified
CNA Linux Linux unaffected 4.18 semver Not specified
CNA Linux Linux unaffected 5.10.261 5.10.* 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 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0fc7069d39239978130c37ebceaec85c8948d3f1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/804bb969f194c93497ba632b98343794c6367fdc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/715eb12e453df752f1b4baaf972c3acff0ab9402 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8dba7a94a269b88e500aafc25ad567ef6a423698 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c9961336aa5ff83092f23e33ee86666a9dbd1b2a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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