CVE-2026-63925 Affecting kernel-default-extra package, versions <6.4.0-150700.53.81.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.35% (26th percentile)

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  • Snyk IDSNYK-SLES157-KERNELDEFAULTEXTRA-19906772
  • published18 Sept 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

NewCVE-2026-63925  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-default-extra to version 6.4.0-150700.53.81.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-extra package and not the kernel-default-extra package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

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).

CVSS Base Scores

version 3.1