{"id":"CVE-2026-98858","summary":"io_uring: fix task_work add use-after-free with SQPOLL","details":"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 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.","modified":"2026-10-19T02:47:37.165442351Z","published":"2026-10-18T15:51:19.578Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98858.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e"},{"type":"WEB","url":"https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98858.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98858"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"af5d68f8892f8ee8f137648b79ceb2abc153a19b"},{"fixed":"42b3332efacfd2140be4cd0dedad4fb96b8ae90e"},{"fixed":"891bd8335a0de3bb15c3b797ce3026bbb0dbef6c"},{"fixed":"395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3"},{"fixed":"a92193c91e8839fe5fc209616ea95465ae4b919d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98858.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.9.0"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.56"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98858.json"}}],"schema_version":"1.9.0"}