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CVE-2026-63925

8.1 · HIGH
Published Jul 19, 2026 EPSS 0.34% (26th pctl)

Overview

CVE-2026-63925 is a high-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

Technical 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).

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Frequently Asked Questions

What is CVE-2026-63925?

CVE-2026-63925 is a high-severity vulnerability. It was published on July 19, 2026 and has a CVSS 3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-63925?

This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-63925?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-63925?

CyberStrike's AI-powered security agents can automatically detect CVE-2026-63925 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.