io_uring: defer eventfd signaling when queued from a wakeup handler
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.114, 6.18.49, 7.1.11, 7.2.1, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-80920
- 2026-10-03 Alias added: GHSA-xg24-c6qm-h882
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-20 Affected versions changed · Red Hat
- 2026-10-20 CVSS score added · Red Hat
- 2026-10-21 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@9d984451baf768ecd9e1fdad4637b729fcb2c9d5 +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-29 Affected versions changed · Red Hat
- 2026-11-01 Affected versions changed · Red Hat
References
Other 6
- https://git.kernel.org/stable/c/d0c240f25e654442a72af5ca021a02165ccce638
- https://git.kernel.org/stable/c/9d984451baf768ecd9e1fdad4637b729fcb2c9d5
- https://git.kernel.org/stable/c/e22f4494cc9487d326e5e3067f33dea7c1e442b2
- https://git.kernel.org/stable/c/b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f
- https://git.kernel.org/stable/c/40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a
- https://git.kernel.org/stable/c/cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e
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Sources
- CVE-2026-80920 · CVE Program
- CVE-2026-80920 · NVD
- FIRST EPSS
- GHSA-xg24-c6qm-h882 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-80920 · Red Hat security data · CC BY 4.0
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