{"id":"CVE-2026-99103","title":"workqueue: Fix unbound pool lifetime for pending pwqs","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix unbound pool lifetime for pending pwqs\n\nKASAN reports a use-after-free of an unbound worker_pool in\nnode_activate_pending_pwq():\n\n  BUG: KASAN: slab-use-…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 5a70baec2294e8a7d0fcc4558741c23e752dad5c < 6741dd3fd38e47c08bc39d11ef5fa141fa6d0441","Linux >= 843288afd3cc6f3342659c6cf81fc47684d25563 < 9f5d5aef3072a33c6f9bfb954bb0cba1c2541849","Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < 390b9542fe670b8936738140ef9f349df6adeab6","Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < f320b85c90fe5fc9d4d06badd450518323a94a7f","Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < 3d2ef2b9f4c084ab498494d26495a82f7e15407b","Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < cf9c8aaea0d47410df8708bec195889f3a85cd3c","Linux fc67aebe34f22632ccb22faea48cc4d3134620a2","Linux >= 6.6.23 < 6.6.25","Linux >= 6.8.2 < 6.8.4","Linux >= 6.7.11 < 6.8","Linux 6.9"],"published":"2026-10-28","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:41:45.076Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99103","references":[{"url":"https://git.kernel.org/stable/c/6741dd3fd38e47c08bc39d11ef5fa141fa6d0441"},{"url":"https://git.kernel.org/stable/c/9f5d5aef3072a33c6f9bfb954bb0cba1c2541849"},{"url":"https://git.kernel.org/stable/c/390b9542fe670b8936738140ef9f349df6adeab6"},{"url":"https://git.kernel.org/stable/c/f320b85c90fe5fc9d4d06badd450518323a94a7f"},{"url":"https://git.kernel.org/stable/c/3d2ef2b9f4c084ab498494d26495a82f7e15407b"},{"url":"https://git.kernel.org/stable/c/cf9c8aaea0d47410df8708bec195889f3a85cd3c"}],"tags":["cve.org"],"epss":0.00173,"epssPercentile":0.06789,"ingestedAt":"2026-10-28T11:09:40.456Z","slug":"CVE-2026-99103","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix unbound pool lifetime for pending pwqs\n\nKASAN reports a use-after-free of an unbound worker_pool in\nnode_activate_pending_pwq():\n\n  BUG: KASAN: slab-use-after-free in _raw_spin_trylock+0x6d/0x120\n  Read of size 4 at addr ffff8880089ce000 by task kworker/u22:0/318\n\n  CPU: 1 UID: 0 PID: 318 Comm: kworker/u22:0 Not tainted 7.2.0 #1 PREEMPT(lazy)\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\n  Workqueue:  0x0 (flush-8:0)\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x53/0x70\n   print_report+0xce/0x610\n   kasan_report+0xce/0x100\n   _raw_spin_trylock+0x6d/0x120\n   pwq_dec_nr_in_flight+0x4b4/0xcb0\n   process_one_work+0x921/0x11a0\n   worker_thread+0x4d0/0xd20\n   kthread+0x2de/0x3c0\n   ret_from_fork+0x3aa/0x620\n   ret_from_fork_asm+0x1a/0x30\n   </TASK>\n\n  Allocated by task 311:\n   alloc_pwq+0x439/0xca0\n   apply_wqattrs_prepare+0x75e/0xd10\n   apply_workqueue_attrs_locked+0x44/0xa0\n   wq_nice_store+0x350/0x450\n\n  Freed by task 0:\n   kfree+0x127/0x3b0\n   rcu_core+0x523/0x1780\n   handle_softirqs+0x1b3/0x610\n\n  Last potentially related work creation:\n   put_unbound_pool+0x3f3/0x7d0\n   pwq_release_workfn+0x494/0x8e0\n   kthread_worker_fn+0x1ff/0x790\n\nCanceling the last inactive work skips pwq_dec_nr_active(), so an empty\npwq can remain on pending_pwqs when its refcnt reaches zero.\npwq_release_workfn() currently puts the pool before removing that pwq.\nIf this drops the last pool reference, the pool can be RCU-freed while\nthe pwq remains reachable, and node_activate_pending_pwq() may trylock\nthe freed pool->lock.\n\nRemove the pwq from pending_pwqs before putting the pool.\n\n## Affected\n\n- `Linux >= 5a70baec2294e8a7d0fcc4558741c23e752dad5c < 6741dd3fd38e47c08bc39d11ef5fa141fa6d0441`\n- `Linux >= 843288afd3cc6f3342659c6cf81fc47684d25563 < 9f5d5aef3072a33c6f9bfb954bb0cba1c2541849`\n- `Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < 390b9542fe670b8936738140ef9f349df6adeab6`\n- `Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < f320b85c90fe5fc9d4d06badd450518323a94a7f`\n- `Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < 3d2ef2b9f4c084ab498494d26495a82f7e15407b`\n- `Linux >= 5797b1c18919cd9c289ded7954383e499f729ce0 < cf9c8aaea0d47410df8708bec195889f3a85cd3c`\n- `Linux fc67aebe34f22632ccb22faea48cc4d3134620a2`\n- `Linux >= 6.6.23 < 6.6.25`\n- `Linux >= 6.8.2 < 6.8.4`\n- `Linux >= 6.7.11 < 6.8`\n- `Linux 6.9`\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":[]}