CVE-2025-21758 Information

Description

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.

Reference

https://git.kernel.org/stable/c/1b91c597b0214b1b462eb627ec02658c944623f2 https://git.kernel.org/stable/c/25195f9d5ffcc8079ad743a50c0409dbdc48d98a https://git.kernel.org/stable/c/a527750d877fd334de87eef81f1cb5f0f0ca3373 https://git.kernel.org/stable/c/d60d493b0e65647e0335e6a7c4547abcea7df8e9 https://git.kernel.org/stable/c/e8af3632a7f2da83e27b083f787bced1faba00b1