CVE-2025-21758: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 16.6% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: add RCU protection to mld_newpack() mld_newpack() can be called without RTNL or RCU being held. 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.

Affected products

• Linux Linux Kernel: from 2.6.26, before 5.15.179 (fixed in 5.15.179); from 5.16, before 6.1.129 (fixed in 6.1.129); from 6.2, before 6.6.79 (fixed in 6.6.79); from 6.7, before 6.12.16 (fixed in 6.12.16); from 6.13, before 6.13.4 (fixed in 6.13.4); version 6.14 only

Published 2025-02-27. Last modified 2026-07-30.