CVE-2025-21765
Linux Kernel 2.6.26 – 5.4.291
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2025-21765 is a medium-severity an unspecified weakness vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).
Operationally, ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SI-16 (Memory Protection) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-5164
Vulnerability Data
In the Linux kernel, the following vulnerability has been resolved: ipv6: use RCU protection in ip6_default_advmss() ip6_default_advmss() needs rcu protection to make sure the net structure it reads does not disappear.
- CWE(s)
Related Threats
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely application of the kernel patch that adds RCU protection to ip6_default_advmss().
Enforces memory-protection techniques that mitigate the use-after-free / structure-lifetime race the missing RCU guard exposes.
Requires process/kernel isolation boundaries that reduce the blast radius if the unprotected net-structure access is exploited.