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
EPSS: 0.074 (93.8th percentile) — read the EPSS interpretation.
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.
Affected products
- Linux — versions b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551, 2.6.26, 0
- Linux 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.