{"id":"CVE-2026-98537","title":"workqueue: Fix NULL current_pwq deref in flush dependency check","summary":"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…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 8ffececcb88262389b4f91fed0fe4884b68204bc","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 9bb739a5c5a570c28a62afb98e9326e2a49743c1","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 513121e69388604619ea8c0ee07e86a3d1b5b5dc","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 0c6b9b1e295aeff1132ac7aa738148cc65f06485","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 1dccf5dc2f8fe688270b261ca4216e03c6a1e674","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < f97e6d0572d1b39998e053732332bc3cfdd0b9aa","Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < db6365ced4d5855e321f772b240c0e473bcfcdd5","Linux 4.5"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:18:05.028Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98537","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"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T15:45:12.278Z","slug":"CVE-2026-98537","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 8ffececcb88262389b4f91fed0fe4884b68204bc`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 9bb739a5c5a570c28a62afb98e9326e2a49743c1`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 513121e69388604619ea8c0ee07e86a3d1b5b5dc`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 0c6b9b1e295aeff1132ac7aa738148cc65f06485`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 1dccf5dc2f8fe688270b261ca4216e03c6a1e674`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < f97e6d0572d1b39998e053732332bc3cfdd0b9aa`\n- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < db6365ced4d5855e321f772b240c0e473bcfcdd5`\n- `Linux 4.5`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}