{"id":"CVE-2026-98537","state":"PUBLISHED","title":"workqueue: Fix NULL current_pwq deref in flush dependency check","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix NULL current_pwq deref in flush dependency check\n\ncheck_flush_dependency() uses current_wq_worker() to determine whether\nthe caller is a workqueue worker and then dereferences worker->current_pwq\nto test whether the current workqueue is WQ_MEM_RECLAIM.\n\ncurrent_wq_worker() only means that %current has PF_WQ_WORKER set. A\nkworker can reach check_flush_dependency() while it is not executing a\nwork item. One such path is worker_thread() acting as the pool manager,\nwhere create_worker() does GFP_KERNEL allocation and the allocation path\ninvokes the OOM notifier. In that state worker->current_pwq is NULL\nbecause current_pwq is set only by process_one_work() and cleared again\nafter the work function returns.\n\n[  416.760634][  T375] Call trace:\n[  416.760638][  T375]  check_flush_dependency+0x80/0x120 (P)\n[  416.760648][  T375]  __flush_work+0x98/0x224\n[  416.760657][  T375]  flush_work+0x30/0x44\n[  416.760665][  T375]  ...\n[  416.760710][  T375]  blocking_notifier_call_chain+0x58/0xa0\n[  416.760719][  T375]  out_of_memory+0xb4/0x458\n[  416.760730][  T375]  __alloc_pages_may_oom+0x11c/0x1a8\n[  416.760739][  T375]  __alloc_pages_slowpath+0x314/0x46c\n[  416.760746][  T375]  __alloc_frozen_pages_noprof+0x110/0x1a4\n[  416.760753][  T375]  new_slab+0x12c/0x484\n[  416.760759][  T375]  ___slab_alloc+0x7a8/0xc7c\n[  416.760765][  T375]  __slab_alloc+0x74/0xd8\n[  416.760772][  T375]  __kmalloc_cache_node_noprof+0x2ac/0x304\n[  416.760779][  T375]  alloc_worker+0x28/0x60\n[  416.760785][  T375]  create_worker+0x4c/0x20c\n[  416.760790][  T375]  worker_thread+0xe8/0x2b8\n[  416.760796][  T375]  kthread+0x1a8/0x200\n[  416.760805][  T375]  ret_from_fork+0x10/0x20\n\nGuard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the\nkworker is not currently executing a work item, there is no current\nworkqueue to diagnose with that warning. The PF_MEMALLOC warning is left\nunchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target\nis still reported.","publishedAt":"2026-10-18T15:18:05.028Z","updatedAt":"2026-10-19T09:21:20.715Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"8ffececcb88262389b4f91fed0fe4884b68204bc","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"9bb739a5c5a570c28a62afb98e9326e2a49743c1","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"513121e69388604619ea8c0ee07e86a3d1b5b5dc","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"0c6b9b1e295aeff1132ac7aa738148cc65f06485","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"1dccf5dc2f8fe688270b261ca4216e03c6a1e674","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"f97e6d0572d1b39998e053732332bc3cfdd0b9aa","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"db6365ced4d5855e321f772b240c0e473bcfcdd5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/workqueue.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.5","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/workqueue.c"]}],"references":["https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc","https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1","https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3","https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc","https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485","https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674","https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa","https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98537.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98537","state":"PUBLISHED","datePublished":"2026-10-18T15:18:05.028Z","dateUpdated":"2026-10-19T09:21:20.715Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.355Z"},"containers":{"cna":{"title":"workqueue: Fix NULL current_pwq deref in flush dependency check","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix NULL current_pwq deref in flush dependency check\n\ncheck_flush_dependency() uses current_wq_worker() to determine whether\nthe caller is a workqueue worker and then dereferences worker->current_pwq\nto test whether the current workqueue is WQ_MEM_RECLAIM.\n\ncurrent_wq_worker() only means that %current has PF_WQ_WORKER set. A\nkworker can reach check_flush_dependency() while it is not executing a\nwork item. One such path is worker_thread() acting as the pool manager,\nwhere create_worker() does GFP_KERNEL allocation and the allocation path\ninvokes the OOM notifier. In that state worker->current_pwq is NULL\nbecause current_pwq is set only by process_one_work() and cleared again\nafter the work function returns.\n\n[  416.760634][  T375] Call trace:\n[  416.760638][  T375]  check_flush_dependency+0x80/0x120 (P)\n[  416.760648][  T375]  __flush_work+0x98/0x224\n[  416.760657][  T375]  flush_work+0x30/0x44\n[  416.760665][  T375]  ...\n[  416.760710][  T375]  blocking_notifier_call_chain+0x58/0xa0\n[  416.760719][  T375]  out_of_memory+0xb4/0x458\n[  416.760730][  T375]  __alloc_pages_may_oom+0x11c/0x1a8\n[  416.760739][  T375]  __alloc_pages_slowpath+0x314/0x46c\n[  416.760746][  T375]  __alloc_frozen_pages_noprof+0x110/0x1a4\n[  416.760753][  T375]  new_slab+0x12c/0x484\n[  416.760759][  T375]  ___slab_alloc+0x7a8/0xc7c\n[  416.760765][  T375]  __slab_alloc+0x74/0xd8\n[  416.760772][  T375]  __kmalloc_cache_node_noprof+0x2ac/0x304\n[  416.760779][  T375]  alloc_worker+0x28/0x60\n[  416.760785][  T375]  create_worker+0x4c/0x20c\n[  416.760790][  T375]  worker_thread+0xe8/0x2b8\n[  416.760796][  T375]  kthread+0x1a8/0x200\n[  416.760805][  T375]  ret_from_fork+0x10/0x20\n\nGuard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the\nkworker is not currently executing a work item, there is no current\nworkqueue to diagnose with that warning. The PF_MEMALLOC warning is left\nunchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target\nis still reported."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"8ffececcb88262389b4f91fed0fe4884b68204bc","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"9bb739a5c5a570c28a62afb98e9326e2a49743c1","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"513121e69388604619ea8c0ee07e86a3d1b5b5dc","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"0c6b9b1e295aeff1132ac7aa738148cc65f06485","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"1dccf5dc2f8fe688270b261ca4216e03c6a1e674","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"f97e6d0572d1b39998e053732332bc3cfdd0b9aa","versionType":"git"},{"version":"fca839c00a12d682cb59b3b620d109a1d850b262","status":"affected","lessThan":"db6365ced4d5855e321f772b240c0e473bcfcdd5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/workqueue.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.5","versionType":"semver"},{"version":"5.10.271","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.112","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.55","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.9","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/workqueue.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc"},{"url":"https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1"},{"url":"https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3"},{"url":"https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc"},{"url":"https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485"},{"url":"https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674"},{"url":"https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa"},{"url":"https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:21:20.715Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"5.10.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.12.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"6.18.55"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"7.2.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.5","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}