{"id":"CVE-2026-98099","published":"2026-09-25T11:17:39.723","lastModified":"2026-09-25T11:17:39.723","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: use rcu_assign_pointer() for __rcu list updates\n\nSeveral places in net/ipv6/mcast.c update RCU-protected lists\n(np->ipv6_mc_list, idev->mc_list, idev->mc_tomb) using direct pointer\nassignments instead of rcu_assign_pointer():\n\n1. In __ipv6_dev_mc_dec(), unlinking a group from idev->mc_list did:\n       *map = ma->next;\n   without rcu_assign_pointer() while concurrent readers traverse\n   idev->mc_list locklessly under rcu_read_lock().\n2. In ipv6_sock_mc_drop() and __ipv6_sock_mc_close(), unlinking a group\n   from np->ipv6_mc_list directly assigned *lnk = mc_lst->next and\n   np->ipv6_mc_list = mc_lst->next without rcu_assign_pointer(), racing\n   with lockless readers in inet6_mc_check().\n3. In __ipv6_sock_mc_join(), mc_lst->next was initialized to\n   np->ipv6_mc_list via raw assignment before publishing mc_lst.\n4. In mld_del_delrec() and __ipv6_dev_mc_inc(), __rcu source pointers\n   passed into rcu_assign_pointer() lacked explicit dereference helpers.\n\nFix these by consistently using rcu_assign_pointer() along with\nmc_dereference() / sock_dereference().","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/0c8f56c583c3250408367880c98e4d6fbc929315","tags":[]},{"url":"https://git.kernel.org/stable/c/2e46b0c9fcf7e10b64ce1630b925f47918d1f7f6","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}