{"id":"CVE-2026-80866","state":"PUBLISHED","title":"tipc: avoid busy looping in tipc_exit_net()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: avoid busy looping in tipc_exit_net()\n\nBlamed commit introduced a busy-wait loop in tipc_exit_net()\nto wait for pending UDP bearer cleanup works to complete:\n\n       while (atomic_read(&tn->wq_count))\n               cond_resched();\n\nThis loop can busy-wait for a long time if cond_resched() is a NOP. This\ntypically happens if the netns exit is executed by a high priority task,\nor under kernels configured without preemption (CONFIG_PREEMPT_NONE). In\nsuch cases, it wastes CPU cycles and can lead to soft lockups.\n\nFix this by replacing the busy loop with wait_var_event(), allowing the\nthread to sleep properly until the work queue count reaches zero.\n\nAccordingly, update cleanup_bearer() to use atomic_dec_and_test() and\nwake_up_var() to wake up the waiter when the count drops to zero.\n\nThis uses the global wait queue hash table, avoiding the need to bloat\nstruct tipc_net with a wait_queue_head_t. The atomic_dec_and_test()\nprovides the necessary memory barrier to ensure the wakeup is not missed.","publishedAt":"2026-09-04T16:48:11.682Z","updatedAt":"2026-10-30T12:31:21.261Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"772769859226a5b004442403510acb58a1c32e72","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"99b82c8452887408ea908fdfa5df33c4a5dfa88f","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"110bb16d37bdba03213156c0df37e7119c190936","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"7672973957e3e20780afe5937a9fec70b72bc060","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"522d1d950b9e3b68190a6de7534827c8dccedb73","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"c1481c94e74c955e0448ddf46b8615a44d840c1e","versionType":"git"},{"version":"d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa","status":"affected","versionType":"git"},{"version":"5195ec5e365a2a9331bfeb585b613a6e94f98dba","status":"affected","versionType":"git"},{"version":"b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d","status":"affected","versionType":"git"},{"version":"5.4.124","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.42","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.12.9","status":"affected","lessThan":"5.13","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/tipc/core.c","net/tipc/udp_media.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/tipc/core.c","net/tipc/udp_media.c"]}],"references":["https://git.kernel.org/stable/c/772769859226a5b004442403510acb58a1c32e72","https://git.kernel.org/stable/c/99b82c8452887408ea908fdfa5df33c4a5dfa88f","https://git.kernel.org/stable/c/110bb16d37bdba03213156c0df37e7119c190936","https://git.kernel.org/stable/c/7672973957e3e20780afe5937a9fec70b72bc060","https://git.kernel.org/stable/c/522d1d950b9e3b68190a6de7534827c8dccedb73","https://git.kernel.org/stable/c/c1481c94e74c955e0448ddf46b8615a44d840c1e"],"weaknesses":[],"ingestedAt":"2026-10-30T12:50:04.827Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/80xxx/CVE-2026-80866.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80866","state":"PUBLISHED","datePublished":"2026-09-04T16:48:11.682Z","dateUpdated":"2026-10-30T12:31:21.261Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.798Z"},"containers":{"cna":{"title":"tipc: avoid busy looping in tipc_exit_net()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: avoid busy looping in tipc_exit_net()\n\nBlamed commit introduced a busy-wait loop in tipc_exit_net()\nto wait for pending UDP bearer cleanup works to complete:\n\n       while (atomic_read(&tn->wq_count))\n               cond_resched();\n\nThis loop can busy-wait for a long time if cond_resched() is a NOP. This\ntypically happens if the netns exit is executed by a high priority task,\nor under kernels configured without preemption (CONFIG_PREEMPT_NONE). In\nsuch cases, it wastes CPU cycles and can lead to soft lockups.\n\nFix this by replacing the busy loop with wait_var_event(), allowing the\nthread to sleep properly until the work queue count reaches zero.\n\nAccordingly, update cleanup_bearer() to use atomic_dec_and_test() and\nwake_up_var() to wake up the waiter when the count drops to zero.\n\nThis uses the global wait queue hash table, avoiding the need to bloat\nstruct tipc_net with a wait_queue_head_t. The atomic_dec_and_test()\nprovides the necessary memory barrier to ensure the wakeup is not missed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"772769859226a5b004442403510acb58a1c32e72","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"99b82c8452887408ea908fdfa5df33c4a5dfa88f","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"110bb16d37bdba03213156c0df37e7119c190936","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"7672973957e3e20780afe5937a9fec70b72bc060","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"522d1d950b9e3b68190a6de7534827c8dccedb73","versionType":"git"},{"version":"04c26faa51d1e2fe71cf13c45791f5174c37f986","status":"affected","lessThan":"c1481c94e74c955e0448ddf46b8615a44d840c1e","versionType":"git"},{"version":"d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa","status":"affected","versionType":"git"},{"version":"5195ec5e365a2a9331bfeb585b613a6e94f98dba","status":"affected","versionType":"git"},{"version":"b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d","status":"affected","versionType":"git"},{"version":"5.4.124","status":"affected","lessThan":"5.5","versionType":"semver"},{"version":"5.10.42","status":"affected","lessThan":"5.11","versionType":"semver"},{"version":"5.12.9","status":"affected","lessThan":"5.13","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/tipc/core.c","net/tipc/udp_media.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/tipc/core.c","net/tipc/udp_media.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/772769859226a5b004442403510acb58a1c32e72"},{"url":"https://git.kernel.org/stable/c/99b82c8452887408ea908fdfa5df33c4a5dfa88f"},{"url":"https://git.kernel.org/stable/c/110bb16d37bdba03213156c0df37e7119c190936"},{"url":"https://git.kernel.org/stable/c/7672973957e3e20780afe5937a9fec70b72bc060"},{"url":"https://git.kernel.org/stable/c/522d1d950b9e3b68190a6de7534827c8dccedb73"},{"url":"https://git.kernel.org/stable/c/c1481c94e74c955e0448ddf46b8615a44d840c1e"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:31:21.261Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4.124"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12.9"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}