Skip to content
Heist/ feed
High

macsec: fix replay protection at XPN lower-PN wrap

Type: advisorySource: Official CVE List1 source record

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).

Announced Source revision 1
Original source ↗

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
Read the original announcement