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).

An update of the linux package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
333941	Photon OS 5.0: Linux PHSA-2026-5.0-92-0926	Nessus	PhotonOS Local Security Checks	Local	high
333762	Photon OS 5.0: Linux PHSA-2026-5.0-92-0895	Nessus	PhotonOS Local Security Checks	Local	high
329326	Photon OS 5.0: Linux PHSA-2026-5.0-0926	Nessus	PhotonOS Local Security Checks	Local	high
328493	Amazon Linux 2023 : bpftool6.12, kernel6.12, kernel6.12-devel (ALAS2023-2026-1968)	Nessus	Amazon Linux Local Security Checks	Local	high
328316	Linux Distros Unpatched Vulnerability : CVE-2026-63925	Nessus	Misc.	Local	high
327380	Amazon Linux 2023 : bpftool, kernel, kernel-devel (ALAS2023-2026-1924)	Nessus	Amazon Linux Local Security Checks	Local	high
325574	Amazon Linux 2 : kernel, --advisory ALAS2KERNEL-5.10-2026-124 (ALASKERNEL-5.10-2026-124)	Nessus	Amazon Linux Local Security Checks	Local	high
322944	Photon OS 5.0: Linux PHSA-2026-5.0-0895	Nessus	PhotonOS Local Security Checks	Local	high
322087	Amazon Linux 2023 : bpftool6.18, kernel6.18, kernel6.18-devel (ALAS2023-2026-1881)	Nessus	Amazon Linux Local Security Checks	Local	high

Detections

Analytics

CVE-2026-63925

high

Tenable Plugins

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