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CVE PROGRAM SOURCE RECORD8.1 High

CVE-2026-63925

macsec: fix replay protection at XPN lower-PN wrap

Description

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).

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • a21ecf0e033807b976967286e6c392f48ee2049f to < dd7306779c6ce1238f4cdc34f3c1f2246b854457affected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < d15130461df388136b62a7b0ce9f66e7e2fa9ff1affected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < 23c0e230eab397d7f68be2538790ac41d3bb91fdaffected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < 679e13a65e68a67c8b3c0467c02ee89157ec6f0faffected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < 79495a1b0944fe31ffd54b54b00211b493590d62affected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < 6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652affected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < d55acbe577db892b60547b6ef1c020b359331a6daffected
  • a21ecf0e033807b976967286e6c392f48ee2049f to < e68842b3356471ba56c882209f324613dac47f64affected

Linux Linux

Default version status: affected

  • 5.7affected
  • 0 to < 5.7unaffected
  • 5.10.259 to ≤ 5.10.*unaffected
  • 5.15.210 to ≤ 5.15.*unaffected
  • 6.1.176 to ≤ 6.1.*unaffected
  • 6.6.143 to ≤ 6.6.*unaffected
  • 6.12.93 to ≤ 6.12.*unaffected
  • 6.18.35 to ≤ 6.18.*unaffected
  • 7.0.12 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References