{"id":"CVE-2026-98858","title":"io_uring: fix task_work add use-after-free with SQPOLL","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix task_work add use-after-free with SQPOLL\n\nFor SQPOLL, the sqpoll thread runs task_work off its own list and\ndoesn't need to be told about it, so it can po…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 42b3332efacfd2140be4cd0dedad4fb96b8ae90e","Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c","Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3","Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < a92193c91e8839fe5fc209616ea95465ae4b919d","Linux 6.9"],"published":"2026-10-18","updated":"2026-10-18","sourceUpdated":"2026-10-18T15:51:19.578Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98858","references":[{"url":"https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e"},{"url":"https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c"},{"url":"https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3"},{"url":"https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d"}],"tags":["cve.org"],"ingestedAt":"2026-10-18T16:47:32.461Z","slug":"CVE-2026-98858","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: fix task_work add use-after-free with SQPOLL\n\nFor SQPOLL, the sqpoll thread runs task_work off its own list and\ndoesn't need to be told about it, so it can pop and complete a request\nas soon as mpscq_push() has published it. If that was the last request\nholding the ring alive, io_ring_exit_work() then frees the ctx, stops\nthe thread, and with it the tctx, while io_req_normal_work_add() is\nstill looking at both after the push:\n\n  BUG: KASAN: slab-use-after-free in io_req_normal_work_add+0x439/0x510\n  Read of size 4 at addr ff11000000ca0000 by task repro/55\n  (...)\n  BUG: KASAN: slab-use-after-free in queue_work_on+0x25/0x70\n  Write of size 8 at addr ff11000000c3bd00 by task repro/55\n\nHold an RCU read lock across the add, like io_req_local_work_add() already\ndoes, and have io_ring_exit_work() wait for a grace period for SQPOLL rings\nas well before freeing the ctx.\n\n## Affected\n\n- `Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 42b3332efacfd2140be4cd0dedad4fb96b8ae90e`\n- `Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 891bd8335a0de3bb15c3b797ce3026bbb0dbef6c`\n- `Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < 395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3`\n- `Linux >= af5d68f8892f8ee8f137648b79ceb2abc153a19b < a92193c91e8839fe5fc209616ea95465ae4b919d`\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":[]}