seg6: validate SRH length before reading fixed fields
In 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.
CVE-2026-72400
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-72400
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "715eb12e453df752f1b4baaf972c3acff0ab9402",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "7247d05c987c3eec4bb7c2306dbd77ecdf3b7c73",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "071f1a38d7ddbadee29c09b9e3ee0ff3a61e6a0e",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "804bb969f194c93497ba632b98343794c6367fdc",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "0fc7069d39239978130c37ebceaec85c8948d3f1",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "8dba7a94a269b88e500aafc25ad567ef6a423698",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "c9961336aa5ff83092f23e33ee86666a9dbd1b2a",
"versionType": "git"
},
{
"status": "affected",
"version": "fe94cc290f535709d3c5ebd1e472dfd0aec7ee79",
"lessThan": "a75d99f46bf21b45965ce39c5cfb3b8bb5ffb1aa",
"versionType": "git"
}
],
"programFiles": [
"net/ipv6/seg6.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.18"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.18",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.261",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.212",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ipv6/seg6.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-72400
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33042 · Revision 1
- Added to Heist Feed
- Publisher date