IT

Tracker / CVE-2026-63925

CVE-2026-63925

High 8.1

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 and versions

linux linux_kernel
linux linux_kernel · 5.11 → 5.15.210
linux linux_kernel · 5.16 → 6.1.176
linux linux_kernel · 5.7 → 5.10.259
linux linux_kernel · 6.13 → 6.18.35
linux linux_kernel · 6.19 → 7.0.12
linux linux_kernel · 6.2 → 6.6.143
linux linux_kernel · 6.7 → 6.12.93

Analysis

This page is not indexable yet.Until it carries original analysis — what it actually exposes, how to check in two minutes whether a system was touched, what to do if it was — the page stays noindex. The database decides that, not the template.

References