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CVE-2026-81010 (GCVE-0-2026-81010)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-14 11:59
VLAI
Title
io_uring/waitid: honor task_work cancellation
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/waitid: honor task_work cancellation io_waitid_cb() may run through the fallback task_work path when task_work_add() can no longer queue work to the originating task. The fallback runs from a kworker and io_uring marks such task work as canceled through tw.cancel. io_waitid_cb() currently ignores tw.cancel and calls __do_wait(). waitid is task-context dependent: __do_wait() performs child lookup relative to current, and the retry path also uses current->signal->wait_chldexit. If the callback runs from the fallback kworker, current is therefore not the task that submitted the request. Honor tw.cancel before entering __do_wait(). Complete the request with -ECANCELED and skip the siginfo copy, since canceled task work may run without the submitting task's userspace execution context. Keep the existing siginfo handling for normal waitid completion and explicit cancellation.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f31ecf671ddc498f20219453395794ff2383e06b , < 0879697520abda2383ed7be40572ad583b5c4b02 (git)
Affected: f31ecf671ddc498f20219453395794ff2383e06b , < 7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c (git)
Affected: f31ecf671ddc498f20219453395794ff2383e06b , < 14572de82e5022899e5856008bc9cac97004a88c (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.18.52 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/waitid.c"
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              "versionType": "original_commit_for_fix"
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          "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-\u003esignal-\u003ewait_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\u0027s userspace execution context.\n\nKeep the existing siginfo handling for normal waitid completion and\nexplicit cancellation."
        }
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "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\u0027s 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\u0027s 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\u0027s mm, and the -ERESTARTSYS retry can add a wait-queue entry on the kworker\u0027s 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."
            }
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        "dateUpdated": "2026-09-14T11:59:42.822Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/0879697520abda2383ed7be40572ad583b5c4b02"
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          "url": "https://git.kernel.org/stable/c/7bc98e2de8c58a2bfaf0f540eb096a386ecfc96c"
        },
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          "url": "https://git.kernel.org/stable/c/14572de82e5022899e5856008bc9cac97004a88c"
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      "title": "io_uring/waitid: honor task_work cancellation",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-81010",
    "datePublished": "2026-09-11T19:43:00.754Z",
    "dateReserved": "2026-08-26T14:34:25.813Z",
    "dateUpdated": "2026-09-14T11:59:42.822Z",
    "state": "PUBLISHED"
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      "date": "2026-09-17",
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      "percentile": "0.03272"
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                "product": "Linux",
                "programFiles": [
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            "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-\u003esignal-\u003ewait_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\u0027s userspace execution context.\n\nKeep the existing siginfo handling for normal waitid completion and\nexplicit cancellation."
          }
        ],
        "id": "CVE-2026-81010",
        "lastModified": "2026-09-14T13:18:55.347",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
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                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "current_release_date": "2026-09-14T21:17:44+00:00",
      "cve": "CVE-2026-81010",
      "id": "CVE-2026-81010",
      "initial_release_date": "2026-09-11T00:00:00+00:00",
      "product_status:known_affected": "185",
      "product_status:known_not_affected": "91",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: io_uring/waitid: honor task_work cancellation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-81010.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-15T01:04:07Z",
      "cve": "CVE-2026-81010",
      "id": "CVE-2026-81010",
      "initial_release_date": "2026-09-12T16:35:37Z",
      "product_status:known_affected": "55",
      "product_status:known_not_affected": "298",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-81010",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-81010.json",
      "version": "4"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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