VulnerabilityPublished 3 Nov 2026

CVE-2026-99262: Linux kernel · io_uring/timeout: don't lose a cancel as io-wq arms a timeout

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in f10ab47077e63d6eee35b242c257c3947bb49e64 : update Linux kernel when convenient.

Data as of 3 Nov 2026, 12:13 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in f10ab47077e63d6eee35b242c257c3947bb49e64, f9d5e02649587885852f46b6dc7c081b87f0ac3a, f1fabf17f37b252b11d8fe5c70c8056b70b005ca +2

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ce35a47a3a0208a77b4d31b7f2e8ed57d624093d, < f10ab47077e63d6eee35b242c257c3947bb49e64	Fixed in f10ab47077e63d6eee35b242c257c3947bb49e64
LinuxLinux	Affected ≥ ce35a47a3a0208a77b4d31b7f2e8ed57d624093d, < f9d5e02649587885852f46b6dc7c081b87f0ac3a	Fixed in f9d5e02649587885852f46b6dc7c081b87f0ac3a
LinuxLinux	Affected ≥ ce35a47a3a0208a77b4d31b7f2e8ed57d624093d, < f1fabf17f37b252b11d8fe5c70c8056b70b005ca	Fixed in f1fabf17f37b252b11d8fe5c70c8056b70b005ca
LinuxLinux	Affected ≥ ce35a47a3a0208a77b4d31b7f2e8ed57d624093d, < df705a274da10da7bb546e08b49fa80a6ef19c78	Fixed in df705a274da10da7bb546e08b49fa80a6ef19c78
LinuxLinux	Affected ≥ ce35a47a3a0208a77b4d31b7f2e8ed57d624093d, < 68cd06ba918d9658c36c1973a0184795738dcc46	Fixed in 68cd06ba918d9658c36c1973a0184795738dcc46
LinuxLinux	Affected =5.6	Fixed in–

AI-suggested

A fix has been implemented in the Linux kernel as indicated by the fixed commit versions. Users should update to a kernel version that includes these fixes to resolve the race condition and prevent tasks from being stuck on timeout cancellation. No additional mitigation is required beyond applying the official patch.

Description

CVE-2026-99262 is a vulnerability in the Linux kernel's io_uring subsystem related to timeout cancellation. A race condition can cause a cancel request to be lost when io-wq arms a timeout, potentially causing a task to be stuck for the full timeout duration during ring exit.

Impact

The impact is that an exiting task can become stuck for the full duration of a timeout due to a lost cancel request in the io_uring timeout handling. This can lead to delays or hangs in task termination but does not indicate privilege escalation or code execution. No known exploits in the wild have been reported.

Summary

The vulnerability involves the io_uring timeout mechanism where an IORING_OP_TIMEOUT operation run by io-wq with IOSQE_ASYNC can lose a cancel request due to a race condition. io_wq_submit_work() checks the IO_WQ_WORK_CANCEL flag only once before issuing the request. If a cancel occurs after this check but before the timeout is armed, the cancel is flagged but not properly handled, causing the timeout to proceed and potentially block the exiting task for the entire timeout period. The fix involves checking the cancel flag under the timeout lock to ensure the request fails if cancellation is detected, preventing the timeout from running unnecessarily.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2026, 12:00 UTC

Technical details

References

Community reviews

Related threats