{"id":"CVE-2026-74609","revision":"b7c4e82ddc07421490be4923f92d0b27","records":[{"revision":"b7c4e82ddc07421490be4923f92d0b27","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-74609","aliases":[],"title":"tipc: read le->link under the node lock in tipc_node_link_down()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: read le->link under the node lock in tipc_node_link_down()\n\ntipc_node_link_down() caches the link pointer before taking n->lock:\n\n\tstruct tipc_link *l = le->link;\t\t/* unlocked */\n\n\tif (!l)\n\t\treturn;\n\ttipc_node_write_lock(n);\n\tif (!tipc_link_is_establishing(l)) {\t/* deref l */\n\t...\n\t\ttipc_link_reset(l);\t\t/* write into l */\n\tif (delete) {\n\t\tkfree(l);\n\t\tle->link = NULL;\n\nThe delete=true caller frees that very object under n->lock, so the lock\ndoes not protect the cached pointer against it:\n\n - CPU A, delete=false: tipc_rcv() on TIPC_LINK_DOWN_EVT, or the link\n supervision timer via tipc_node_timeout(), reads l unlocked and then\n dereferences it under n->lock;\n - CPU B, delete=true: netlink TIPC_NL_BEARER_DISABLE -> bearer_disable()\n -> tipc_node_delete_links() -> tipc_node_link_down(n, bearer_id, true)\n -> kfree(l).\n\nThe link is freed with plain kfree(), not kfree_rcu(), and for UDP bearers\ndisable_media() only schedules the asynchronous cleanup_bearer() work, so\nits synchronize_net() runs after the links are already gone. An in-flight\nCPU A that has read l therefore dereferences freed memory once B frees it:\na use-after-free read in tipc_link_is_establishing(), and a use-after-free\nwrite via tipc_link_reset() on the establishing branch.\n\nThe following trace was captured on 7.2.0-rc5-00284-gaf39eb111ce6:\n\n BUG: KASAN: slab-use-after-free in tipc_link_is_establishing (net/tipc/link.c:285)\n Read of size 4 at addr ffff88802e2aa068 by task swapper/2/0\n tipc_link_is_establishing (net/tipc/link.c:285)\n tipc_node_link_down (net/tipc/node.c:1076)\n tipc_node_timeout (net/tipc/node.c:843)\n Allocated by task 9549:\n tipc_link_create (net/tipc/link.c:490)\n tipc_node_check_dest (net/tipc/node.c:1279)\n tipc_disc_rcv (net/tipc/discover.c:252)\n tipc_udp_recv (net/tipc/udp_media.c:389)\n Freed by task 9549:\n tipc_node_link_down (net/tipc/node.c:1084)\n tipc_node_delete_links (net/tipc/node.c:1320)\n bearer_disable (net/tipc/bearer.c:414)\n __tipc_nl_bearer_disable (net/tipc/bearer.c:992)\n\nMove the le->link read inside tipc_node_write_lock(), so it is serialised\nagainst the kfree() in the delete path. A racing teardown now either has\nnot run yet, and we see a valid link, or has already run, and we see NULL.","state":0,"publishedAt":"2026-08-22T15:31:56.054+00:00","modifiedAt":"2026-10-16T19:06:01.059+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/tipc/node.c\"\n ],\n \"versions\": [\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"2be741ad565c610871a6a95062c12c39da7168fd\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"69d209461c110388710e483a130caf051e4fd09a\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"de017c22135f545ca4e65d1eada22887b64958eb\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"47ba70891b10b2feb52462086b7fcd2ad75d3ce3\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"a714d62513befef37f71f4ae89bb1fe173b65f2e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"c3f2347a47754eac690967cfd82cb6d559817b07\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"5558a8312452ddb21eff22b1cbd84302ad951944\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"73f646cec35477b5099d7e952297cb9e1855be45\",\n \"lessThan\": \"cba9ccb47e9fa4cc77692fb896cc5ab57a667882\",\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/tipc/node.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.4\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.4\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.265\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.216\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.183\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.152\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.104\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.45\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.1.9\",\n \"lessThanOrEqual\": \"7.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/2be741ad565c610871a6a95062c12c39da7168fd","https://git.kernel.org/stable/c/69d209461c110388710e483a130caf051e4fd09a","https://git.kernel.org/stable/c/de017c22135f545ca4e65d1eada22887b64958eb","https://git.kernel.org/stable/c/47ba70891b10b2feb52462086b7fcd2ad75d3ce3","https://git.kernel.org/stable/c/a714d62513befef37f71f4ae89bb1fe173b65f2e","https://git.kernel.org/stable/c/c3f2347a47754eac690967cfd82cb6d559817b07","https://git.kernel.org/stable/c/5558a8312452ddb21eff22b1cbd84302ad951944","https://git.kernel.org/stable/c/cba9ccb47e9fa4cc77692fb896cc5ab57a667882"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74609","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-74609","identifiers":["CVE-2026-74609"]},"retained":false,"historicalAffected":[]}],"coverage":[]}