# CVE-2026-99263: io_uring/poll: avoid retry wakeup loss when dropping ownership

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

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

io_uring/poll: avoid retry wakeup loss when dropping ownership

If a wakeup sets IO_POLL_RETRY_FLAG between the owning task consuming
the existing instance of IO_POLL_RETRY_FLAG and the loop check
of io_poll_check_events(), then we stall on processing the request
until an unrelated wakeup comes along.

Using atomic_cmpxchg instead of atomic_sub_return to guarantee both the
count v and poll_refs are 0 and no wake-ups are missed.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < d1f6850086ac6f8b0fa44fb19aa2a468c73ee071 (affected, git); ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < 41fae2e9e1fa3bee86aee0a25ba90e59ce5024bf (affected, git); ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < 4ef685b8505615729d75c875f52822238bf76ca6 (affected, git); ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < afa407c02f3aa0fd872f86c9bf1b34502e0fa8f0 (affected, git); ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < eb2a50d8235e4580fea9aa20f3fbe1a002c38cb1 (affected, git); ≥ a26a35e9019fd70bf3cf647dcfdae87abc7bacea; < 521e8a65e9b45532295ba1082ef12be6e80c173b (affected, git); 4b702b7d11ce1b9d26fc6d7c5a7ef4ac1d455048 (affected, git); bc4e6ee16778149811333a969a7a893d4cc110c5 (affected, git); ≥ 5.15.82; < 5.16 (affected, semver); ≥ 6.0.11; < 6.1 (affected, semver). Source: CNA: Linux
- Linux / Linux: 6.1 (affected); ≥ 0; < 6.1 (unaffected, semver); ≥ 6.1.191; ≤ 6.1.* (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); ≥ 7.3.1; ≤ 7.3.* (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/d1f6850086ac6f8b0fa44fb19aa2a468c73ee071 (CNA: Linux)

- https://git.kernel.org/stable/c/41fae2e9e1fa3bee86aee0a25ba90e59ce5024bf (CNA: Linux)

- https://git.kernel.org/stable/c/4ef685b8505615729d75c875f52822238bf76ca6 (CNA: Linux)

- https://git.kernel.org/stable/c/afa407c02f3aa0fd872f86c9bf1b34502e0fa8f0 (CNA: Linux)

- https://git.kernel.org/stable/c/eb2a50d8235e4580fea9aa20f3fbe1a002c38cb1 (CNA: Linux)

- https://git.kernel.org/stable/c/521e8a65e9b45532295ba1082ef12be6e80c173b (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-99263; retrieved 2026-11-03; source updated 2026-11-03

Revision: 06743dc03f765af88bff81530fe09d9c5ff3a26ee1125338c923dfc12dce9b1a

Canonical: https://y2.dev/cve/CVE-2026-99263

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