Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: use rcu_assign_pointer() for __rcu list updates Several places in net/ipv6/mcast.c update RCU-protected lists (np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer assignments instead of rcu_assign_pointer(): 1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did: *map = ma->next; without rcu_assign_pointer() while concurrent readers traverse idev->mc_list locklessly under rcu_read_lock(). 2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing with lockless readers in inet6_mc_check(). 3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to np->ipv6_mc_list via raw assignment before publishing mc_lst. 4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers passed into rcu_assign_pointer() lacked explicit dereference helpers. Fix these by consistently using rcu_assign_pointer() along with mc_dereference() / sock_dereference().
Affected products
linux: linux kernel
References5
- git.kernel.org/stable/c/0c8f56c583c3250408367880c98e4d6fbc929315 Patch
- git.kernel.org/stable/c/0e3e3cec28c4d1bf29948da40b4e9e5d44f7852b Patch
- git.kernel.org/stable/c/2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6 Patch
- git.kernel.org/stable/c/49d7e1b456ba2f3ee08b3e264d999c09992cde8e Patch
- git.kernel.org/stable/c/afca229b39acc2590976b3e4f6e0fe76cededc60 Patch
Metrics
- CVSS 3.1
-
4.7
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 0 · as of 9 November 2026
- CWE
- CWE-362
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