macsec: fix replay protection at XPN lower-PN wrap
In the Linux kernel, the following vulnerability has been resolved: macsec: fix replay protection at XPN lower-PN wrap In macsec_post_decrypt(), when pn is U32_MAX, pn + 1 overflows u32 to 0 and the first branch never fires. If next_pn_halves.lower is also in the upper half, pn_same_half(pn, lower) is true and the XPN else-if does not fire either, leaving next_pn_halves unchanged. An attacker that captures the legitimate frame carrying pn == 0xFFFFFFFF on an XPN association can then replay it indefinitely, since lowest_pn never rises above the captured pn and macsec_decrypt() reconstructs the same IV. Extend the XPN else-if to also fire when pn + 1 wraps to 0, so receipt of pn == U32_MAX advances next_pn_halves to (upper + 1, 0).
CVE-2026-63925
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-2026-63925
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": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "dd7306779c6ce1238f4cdc34f3c1f2246b854457",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "d15130461df388136b62a7b0ce9f66e7e2fa9ff1",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "23c0e230eab397d7f68be2538790ac41d3bb91fd",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "679e13a65e68a67c8b3c0467c02ee89157ec6f0f",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "79495a1b0944fe31ffd54b54b00211b493590d62",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "d55acbe577db892b60547b6ef1c020b359331a6d",
"versionType": "git"
},
{
"status": "affected",
"version": "a21ecf0e033807b976967286e6c392f48ee2049f",
"lessThan": "e68842b3356471ba56c882209f324613dac47f64",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/macsec.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.7"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.7",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.259",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.210",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.176",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.143",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.93",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.35",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.12",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/macsec.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-63925
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40898 · Revision 1
- Added to Heist Feed
- Publisher date