{"id":"CVE-2026-81010","state":"PUBLISHED","title":"io_uring/waitid: honor task_work cancellation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/waitid: honor task_work cancellation\n\nio_waitid_cb() may run through the fallback task_work path when\ntask_work_add() can no longer queue work to the originating task. The\nfallback runs from a kworker and io_uring marks such task work as\ncanceled through tw.cancel.\n\nio_waitid_cb() currently ignores tw.cancel and calls __do_wait().\nwaitid is task-context dependent: __do_wait() performs child lookup\nrelative to current, and the retry path also uses\ncurrent->signal->wait_chldexit. If the callback runs from the fallback\nkworker, current is therefore not the task that submitted the request.\n\nHonor tw.cancel before entering __do_wait(). Complete the request with\n-ECANCELED and skip the siginfo copy, since canceled task work may run\nwithout the submitting task's userspace execution context.\n\nKeep the existing siginfo handling for normal waitid completion and\nexplicit cancellation.","publishedAt":"2026-09-11T19:43:00.754Z","updatedAt":"2026-10-19T08:46:35.449Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"0879697520abda2383ed7be40572ad583b5c4b02","versionType":"git"},{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c","versionType":"git"},{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"14572de82e5022899e5856008bc9cac97004a88c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/waitid.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","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/waitid.c"]}],"references":["https://git.kernel.org/stable/c/0879697520abda2383ed7be40572ad583b5c4b02","https://git.kernel.org/stable/c/7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c","https://git.kernel.org/stable/c/14572de82e5022899e5856008bc9cac97004a88c"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/81xxx/CVE-2026-81010.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81010","state":"PUBLISHED","datePublished":"2026-09-11T19:43:00.754Z","dateUpdated":"2026-10-19T08:46:35.449Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-26T14:34:25.813Z"},"containers":{"cna":{"title":"io_uring/waitid: honor task_work cancellation","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/waitid: honor task_work cancellation\n\nio_waitid_cb() may run through the fallback task_work path when\ntask_work_add() can no longer queue work to the originating task. The\nfallback runs from a kworker and io_uring marks such task work as\ncanceled through tw.cancel.\n\nio_waitid_cb() currently ignores tw.cancel and calls __do_wait().\nwaitid is task-context dependent: __do_wait() performs child lookup\nrelative to current, and the retry path also uses\ncurrent->signal->wait_chldexit. If the callback runs from the fallback\nkworker, current is therefore not the task that submitted the request.\n\nHonor tw.cancel before entering __do_wait(). Complete the request with\n-ECANCELED and skip the siginfo copy, since canceled task work may run\nwithout the submitting task's userspace execution context.\n\nKeep the existing siginfo handling for normal waitid completion and\nexplicit cancellation."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"0879697520abda2383ed7be40572ad583b5c4b02","versionType":"git"},{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c","versionType":"git"},{"version":"f31ecf671ddc498f20219453395794ff2383e06b","status":"affected","lessThan":"14572de82e5022899e5856008bc9cac97004a88c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["io_uring/waitid.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.7","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.7","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.4","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/waitid.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/0879697520abda2383ed7be40572ad583b5c4b02"},{"url":"https://git.kernel.org/stable/c/7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c"},{"url":"https://git.kernel.org/stable/c/14572de82e5022899e5856008bc9cac97004a88c"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The bug is reached by submitting IORING_OP_WAITID via io_uring_setup/io_uring_enter, then forcing canceled task_work by closing the ring or exiting the submitting task. Per kernel scoring guidance, io_uring bugs are Local.\nAC:L - The attacker controls the full sequence: create a DEFER_TASKRUN ring, submit WAITID, fork/signal children so io_waitid_wait queues io_waitid_cb, then close the ring so io_ring_exit_work runs that callback from a kworker with tw.cancel set. No uninfluenced race or rare config is required.\nPR:L - Unprivileged users can create an io_uring ring (sysctl_io_uring_disabled defaults to 0) and IORING_OP_WAITID has no capability check; waiting on one's own children needs no privilege. User namespaces or init-namespace root are not required.\nUI:N - The attacker performs every step in their own process (ring setup, WAITID submission, child fork/signal, and ring close or exit). No other user must act.\nS:U - Wrong-context waitid completion and the resulting kernel memory corruption stay within the host kernel's security authority. This is standard local privilege-escalation/DoS impact, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - Ignoring tw.cancel lets io_waitid_cb run __do_wait and unsafe_put_user of siginfo from a PF_KTHREAD fallback worker whose lazy-TLB CR3 may be another mm, including one concurrently torn down by exit_mmap, yielding memory corruption over reused pages/page tables that can be leveraged for kernel disclosure.\nI:H - The same kworker path writes siginfo fields through unsafe_put_user to an attacker-chosen userspace address without the submitter's mm, and the -ERESTARTSYS retry can add a wait-queue entry on the kworker's wait_chldexit. Wrong-mm writes and wait-queue corruption are High-integrity primitives.\nA:H - Userspace access against a missing or tearing-down mm, and wait-queue manipulation on the wrong task, produce kernel faults, oopses, and panics; the unexploited fallback path can also crash or hang ring-teardown. Any kernel crash is High availability."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:46:35.449Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.2.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}