{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-81010", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-26T14:34:25.813Z", "datePublished": "2026-09-11T19:43:00.754Z", "dateUpdated": "2026-10-19T08:46:35.449Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:46:35.449Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/waitid.c" ], "versions": [ { "version": "f31ecf671ddc498f20219453395794ff2383e06b", "lessThan": "0879697520abda2383ed7be40572ad583b5c4b02", "status": "affected", "versionType": "git" }, { "version": "f31ecf671ddc498f20219453395794ff2383e06b", "lessThan": "7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c", "status": "affected", "versionType": "git" }, { "version": "f31ecf671ddc498f20219453395794ff2383e06b", "lessThan": "14572de82e5022899e5856008bc9cac97004a88c", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/waitid.c" ], "versions": [ { "version": "6.7", "status": "affected" }, { "version": "0", "lessThan": "6.7", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "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" } ] } ] } ], "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" } ], "title": "io_uring/waitid: honor task_work cancellation", "x_generator": { "engine": "bippy-1.2.0" } } } }