Use After Free in Linux

CVE-2025-21759

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.

Vulnerability class: Use-After-Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.078 (94.5th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-21759: held from 0.074 to 0.078.

EPSS over last 30 days · oldest: 0.074 · newest: 0.078 · change: +0.004

Affected products

  • Linux — versions b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, 2.6.26, 0
  • Linux Kernel — versions 6.14

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-21759?
CVE-2025-21759 is a high-severity vulnerability in Linux, classified under Use After Free. CVSS score: 7.8/10. Published 2025-02-27.
How severe is CVE-2025-21759?
High severity. CVSS v3 base score is 7.8 out of 10.