# CVE-2026-99268: io_uring: wake ring pollers for local task_work

Status: published. Published: 2026-11-03. Updated: 2026-11-03.

In the Linux kernel, the following vulnerability has been resolved:

io_uring: wake ring pollers for local task_work

With IORING_SETUP_DEFER_TASKRUN completions are queued as local work, and
only become CQEs when the submitter enters the kernel to wait for events.
For an application that finds out via poll() or epoll on the ring fd when
it is time to do that, io_uring_poll() reports EPOLLIN if local work is
pending.

That only helps if the work is there at the time of the call. When
DEFER_TASKRUN was added, io_req_local_work_add() did io_cqring_wake(),
which took care of tasks sleeping in poll() as well. Then polling got a
wait queue of its own, ->poll_wq, and the wake up in
io_req_local_work_add() was replaced by waking the submitter directly.
Since then ->poll_wq is only woken when CQEs are committed, which for
such a ring is done by the very task that is waiting to be told to:

  submitter                           completion
  poll(ring_fd)
    io_uring_poll()  // nothing yet
    schedule()
                                      io_req_local_work_add()
                                        // ->cq_wait_nr: nobody waits
  // sleeps on

Wake ->poll_wq when the first entry is put on the work list. Like for the
eventfd, that must not be done right away if the work is queued from a
wake up handler, as the chain of wake ups could get back to the wait
queue whose lock is held. Use an RCU callback in that case, with a
reference to the ring.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 130bd686d9be918e4cc8c03abf5794ba2d860502; < 9bb28e7740ce78beecafc5db074b45f4cbeb8a47 (affected, git); ≥ 130bd686d9be918e4cc8c03abf5794ba2d860502; < d8c618747a6aa90022e19ec614aa7157d0302108 (affected, git); ≥ 130bd686d9be918e4cc8c03abf5794ba2d860502; < 2c88d978f1dfd03edf67924ea8fd25cc45499eef (affected, git); ≥ 130bd686d9be918e4cc8c03abf5794ba2d860502; < 92bfadcbe0a9a001beb5e58a2abaf040b873deb6 (affected, git). Source: CNA: Linux
- Linux / Linux: 6.3 (affected); ≥ 0; < 6.3 (unaffected, semver); ≥ 6.6.161; ≤ 6.6.* (unaffected, semver); ≥ 6.12.115; ≤ 6.12.* (unaffected, semver); ≥ 6.18.60; ≤ 6.18.* (unaffected, semver); ≥ 7.2.14; ≤ 7.2.* (unaffected, semver). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/9bb28e7740ce78beecafc5db074b45f4cbeb8a47 (CNA: Linux)

- https://git.kernel.org/stable/c/d8c618747a6aa90022e19ec614aa7157d0302108 (CNA: Linux)

- https://git.kernel.org/stable/c/2c88d978f1dfd03edf67924ea8fd25cc45499eef (CNA: Linux)

- https://git.kernel.org/stable/c/92bfadcbe0a9a001beb5e58a2abaf040b873deb6 (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99268; retrieved 2026-11-03; source updated 2026-11-03

Revision: 86c6670b0506fc0ae2f914b1c1e6ba3812fd4b2704c9c8a4374026f49c071316

Canonical: https://y2.dev/cve/CVE-2026-99268

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