{"api_version":"1","generated_at":"2026-08-22T19:32:47+00:00","cve":"CVE-2026-74609","urls":{"html":"https://cve.report/CVE-2026-74609","api":"https://cve.report/api/cve/CVE-2026-74609.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74609","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74609"},"summary":{"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":"PUBLISHED","assigner":"Linux","published_at":"2026-08-22 16:16:33","updated_at":"2026-08-22 16:16:33"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/5558a8312452ddb21eff22b1cbd84302ad951944","name":"https://git.kernel.org/stable/c/5558a8312452ddb21eff22b1cbd84302ad951944","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/c3f2347a47754eac690967cfd82cb6d559817b07","name":"https://git.kernel.org/stable/c/c3f2347a47754eac690967cfd82cb6d559817b07","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/47ba70891b10b2feb52462086b7fcd2ad75d3ce3","name":"https://git.kernel.org/stable/c/47ba70891b10b2feb52462086b7fcd2ad75d3ce3","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/cba9ccb47e9fa4cc77692fb896cc5ab57a667882","name":"https://git.kernel.org/stable/c/cba9ccb47e9fa4cc77692fb896cc5ab57a667882","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/de017c22135f545ca4e65d1eada22887b64958eb","name":"https://git.kernel.org/stable/c/de017c22135f545ca4e65d1eada22887b64958eb","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/69d209461c110388710e483a130caf051e4fd09a","name":"https://git.kernel.org/stable/c/69d209461c110388710e483a130caf051e4fd09a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2be741ad565c610871a6a95062c12c39da7168fd","name":"https://git.kernel.org/stable/c/2be741ad565c610871a6a95062c12c39da7168fd","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a714d62513befef37f71f4ae89bb1fe173b65f2e","name":"https://git.kernel.org/stable/c/a714d62513befef37f71f4ae89bb1fe173b65f2e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74609","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74609","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 2be741ad565c610871a6a95062c12c39da7168fd git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 69d209461c110388710e483a130caf051e4fd09a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 de017c22135f545ca4e65d1eada22887b64958eb git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 47ba70891b10b2feb52462086b7fcd2ad75d3ce3 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 a714d62513befef37f71f4ae89bb1fe173b65f2e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 c3f2347a47754eac690967cfd82cb6d559817b07 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 5558a8312452ddb21eff22b1cbd84302ad951944 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 73f646cec35477b5099d7e952297cb9e1855be45 cba9ccb47e9fa4cc77692fb896cc5ab57a667882 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.4","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.4 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.10.265 5.10.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.216 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.183 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.152 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.104 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.45 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.9 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/tipc/node.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"2be741ad565c610871a6a95062c12c39da7168fd","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"69d209461c110388710e483a130caf051e4fd09a","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"de017c22135f545ca4e65d1eada22887b64958eb","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"47ba70891b10b2feb52462086b7fcd2ad75d3ce3","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"a714d62513befef37f71f4ae89bb1fe173b65f2e","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"c3f2347a47754eac690967cfd82cb6d559817b07","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"5558a8312452ddb21eff22b1cbd84302ad951944","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"},{"lessThan":"cba9ccb47e9fa4cc77692fb896cc5ab57a667882","status":"affected","version":"73f646cec35477b5099d7e952297cb9e1855be45","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/tipc/node.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.4"},{"lessThan":"4.4","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.265","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.216","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.183","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.152","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.104","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.45","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.9","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.265","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.216","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.183","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.152","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.104","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.45","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.9","versionStartIncluding":"4.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"4.4","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-08-22T15:31:56.054Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2be741ad565c610871a6a95062c12c39da7168fd"},{"url":"https://git.kernel.org/stable/c/69d209461c110388710e483a130caf051e4fd09a"},{"url":"https://git.kernel.org/stable/c/de017c22135f545ca4e65d1eada22887b64958eb"},{"url":"https://git.kernel.org/stable/c/47ba70891b10b2feb52462086b7fcd2ad75d3ce3"},{"url":"https://git.kernel.org/stable/c/a714d62513befef37f71f4ae89bb1fe173b65f2e"},{"url":"https://git.kernel.org/stable/c/c3f2347a47754eac690967cfd82cb6d559817b07"},{"url":"https://git.kernel.org/stable/c/5558a8312452ddb21eff22b1cbd84302ad951944"},{"url":"https://git.kernel.org/stable/c/cba9ccb47e9fa4cc77692fb896cc5ab57a667882"}],"title":"tipc: read le->link under the node lock in tipc_node_link_down()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74609","datePublished":"2026-08-22T15:31:56.054Z","dateReserved":"2026-08-15T05:44:03.920Z","dateUpdated":"2026-08-22T15:31:56.054Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-22 16:16:33","lastModifiedDate":"2026-08-22 16:16:33","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74609","Ordinal":"1","Title":"tipc: read le->link under the node lock in tipc_node_link_down()","CVE":"CVE-2026-74609","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74609","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"tipc: read le->link under the node lock in tipc_node_link_down()"}]}}}