{"id":"CVE-2026-99117","revision":"b02488d0bbfb4ffd95c3cafa6f0f3349","records":[{"revision":"b02488d0bbfb4ffd95c3cafa6f0f3349","observedAt":"2026-10-28T11:27:43.363+00:00","statement":{"source":"cve-program","id":"CVE-2026-99117","aliases":[],"title":"net: bridge: mcast: don't truncate the port group walk on teardown","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: don't truncate the port group walk on teardown\n\n__br_multicast_disable_port_ctx() and br_multicast_del_port() walk\nport->mglist with hlist_for_each_entry_safe(). However,\nbr_multicast_find_del_pg() can also delete other entries from the same\nlist through br_multicast_fwd_src_remove() or __fwd_del_star_excl().\n\nIf such an entry is the iterator's saved next node, hlist_del_init()\nclears its ->next and terminates the walk early. The reproducer triggers\nthis in both teardown walks, leaving port groups in the bridge mdb with\na dangling ->key.port after del_nbp() frees the port:\n\n  BUG: KASAN: slab-use-after-free in __mdb_fill_info+0x1191/0x1320\n   __mdb_fill_info+0x1191/0x1320\n   br_mdb_dump+0x594/0xe40\n   rtnl_mdb_dump+0x1cf/0x5d0\n\nUse hlist_del_init_rcu() to unlink the group while preserving ->next.\nbr_multicast_del_pg() and the teardown walks run under\nbr->multicast_lock. The GC worker must acquire the same lock before\ndetaching the group for destruction, so the node remains alive while\nthe walk uses the preserved pointer.\n\nPreserving ->next means a walk can now reach a group that an earlier\niteration already deleted as a side effect. That group is off mp->ports,\nso br_multicast_find_del_pg() would fall through its port scan and hit\nthe trailing WARN_ON(1). Skip such groups at the top of that helper: a\nport group is put on port->mglist when it is created and only unlinked\nwhen it is deleted, so hlist_unhashed() identifies exactly this case.","state":0,"publishedAt":"2026-10-28T10:34:33.874+00:00","modifiedAt":"2026-10-28T10:34:33.874+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/bridge/br_multicast.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2\",\n                            \"lessThan\": \"8243d587a081e790ad96e80d48eef44d9f7ef005\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2\",\n                            \"lessThan\": \"b45e8c24608c992d1e2cea047eb5bcbfa537f86b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"b08123684bd55fa6d6ee4b52d4ae3040fadb5aa2\",\n                            \"lessThan\": \"5a3f7a683aee56e1f15c9d53041f3236767eaae7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/bridge/br_multicast.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5.10\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"5.10\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.59\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.13\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/8243d587a081e790ad96e80d48eef44d9f7ef005","https://git.kernel.org/stable/c/b45e8c24608c992d1e2cea047eb5bcbfa537f86b","https://git.kernel.org/stable/c/5a3f7a683aee56e1f15c9d53041f3236767eaae7"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99117","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99117","identifiers":["CVE-2026-99117"]},"retained":false,"historicalAffected":[]}],"coverage":[]}