{"id":"CVE-2026-98858","state":"PUBLISHED","title":"io_uring: fix task_work add use-after-free with SQPOLL","description":"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.","publishedAt":"2026-10-18T15:51:19.578Z","updatedAt":"2026-10-19T09:26:52.852Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"42b3332efacfd2140be4cd0dedad4fb96b8ae90e","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"891bd8335a0de3bb15c3b797ce3026bbb0dbef6c","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"a92193c91e8839fe5fc209616ea95465ae4b919d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/io_uring.c","io_uring/tw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","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":["io_uring/io_uring.c","io_uring/tw.c"]}],"references":["https://git.kernel.org/stable/c/42b3332efacfd2140be4cd0dedad4fb96b8ae90e","https://git.kernel.org/stable/c/891bd8335a0de3bb15c3b797ce3026bbb0dbef6c","https://git.kernel.org/stable/c/395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3","https://git.kernel.org/stable/c/a92193c91e8839fe5fc209616ea95465ae4b919d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98858.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98858","state":"PUBLISHED","datePublished":"2026-10-18T15:51:19.578Z","dateUpdated":"2026-10-19T09:26:52.852Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.376Z"},"containers":{"cna":{"title":"io_uring: fix task_work add use-after-free with SQPOLL","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"42b3332efacfd2140be4cd0dedad4fb96b8ae90e","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"891bd8335a0de3bb15c3b797ce3026bbb0dbef6c","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"395b25968fe854d4efaa19a8e9b7a5b6d1b3eea3","versionType":"git"},{"version":"af5d68f8892f8ee8f137648b79ceb2abc153a19b","status":"affected","lessThan":"a92193c91e8839fe5fc209616ea95465ae4b919d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/io_uring.c","io_uring/tw.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","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":["io_uring/io_uring.c","io_uring/tw.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:26:52.852Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}