CVE-2026-63925
Linux macsec XPN replay bug allows indefinite replay when PN wraps
Is CVE-2026-63925 being exploited?
Not confirmed. CVE-2026-63925 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.34% probability of exploitation in the next 30 days.
How severe is CVE-2026-63925?
CVE-2026-63925 is rated High with a CVSS score of 8.1. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-63925?
Yes. A fix has been recorded for CVE-2026-63925. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-63925 affect?
CVE-2026-63925 affects Linux kernel (macsec/XPN), Linux-based routers/switches, Embedded appliances using macsec. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-63925?
Install kernel updates with the macsec XPN fix; disable macsec XPN if you cannot patch immediately.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Indefinite replay of captured MACsec XPN frames when PN wraps, enabling packet replay, replay‑protection bypass, and potential session disruption or data injection.
Patch when possible
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < dd7306779c6ce1238f4cdc34f3c1f2246b854457
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < d15130461df388136b62a7b0ce9f66e7e2fa9ff1
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < 23c0e230eab397d7f68be2538790ac41d3bb91fd
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < 679e13a65e68a67c8b3c0467c02ee89157ec6f0f
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < 79495a1b0944fe31ffd54b54b00211b493590d62
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < 6d00f5c7e5ff7ec4795b7f5f8ed88bd346641652
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < d55acbe577db892b60547b6ef1c020b359331a6d
- affected>= a21ecf0e033807b976967286e6c392f48ee2049f and < e68842b3356471ba56c882209f324613dac47f64
- affected5.7
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.