VulnerabilityPublished 3 Nov 2026

CVE-2026-99255: Linux kernel · io_uring/io-wq: don't hide a link from cancellations

Source GCVE Database

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Authoritative record:CVE-2026-99255· Medium

Not known to be exploited · fixed in ebe8e97fb99d9f374c482902a00677cfd24a6c27 : update Linux kernel when convenient.

Data as of 3 Nov 2026, 13:15 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 ebe8e97fb99d9f374c482902a00677cfd24a6c27, d39ebc7a583d650b1d6da9b45e2ce96ad4d877e4, 98470f164286f7f62aaee519d4d11b9370ce6d7b +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.

ghsa-v9jm-vmfj-9vh2

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 768134d4f48109b90f4248feecbeeb7d684e410c, < ebe8e97fb99d9f374c482902a00677cfd24a6c27	Fixed in ebe8e97fb99d9f374c482902a00677cfd24a6c27
LinuxLinux	Affected ≥ 768134d4f48109b90f4248feecbeeb7d684e410c, < d39ebc7a583d650b1d6da9b45e2ce96ad4d877e4	Fixed in d39ebc7a583d650b1d6da9b45e2ce96ad4d877e4
LinuxLinux	Affected ≥ 768134d4f48109b90f4248feecbeeb7d684e410c, < 98470f164286f7f62aaee519d4d11b9370ce6d7b	Fixed in 98470f164286f7f62aaee519d4d11b9370ce6d7b
LinuxLinux	Affected ≥ 768134d4f48109b90f4248feecbeeb7d684e410c, < 92e20e9c72bdf6cfa6f84eded7b33399bc7061da	Fixed in 92e20e9c72bdf6cfa6f84eded7b33399bc7061da
LinuxLinux	Affected ≥ 768134d4f48109b90f4248feecbeeb7d684e410c, < 3e02b8df0e9fa1423ac2a4e03409a9329c30ac49	Fixed in 3e02b8df0e9fa1423ac2a4e03409a9329c30ac49
LinuxLinux	Affected =5.5	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

No explicit vendor advisory or patch link is provided in the data. If you cannot patch yet, avoid workloads that heavily rely on asynchronous linked io_uring requests during thread or process exit to reduce the risk of hangs.

Description

CVE-2026-99255 is a vulnerability in the Linux kernel's io_uring subsystem related to cancellation handling of linked requests. A timing window exists during the freeing of linked requests where the next request in the link is temporarily invisible to cancellation logic, causing tasks to sleep indefinitely and potentially hang during exit. This can lead to threads or processes being unable to terminate properly.

Impact

The impact is that tasks (threads or processes) performing asynchronous linked io_uring operations may hang indefinitely during exit due to the cancellation logic missing linked requests temporarily. This can cause resource leaks and prevent proper termination of threads or processes, potentially affecting system stability and responsiveness under workloads using io_uring with linked requests.

References

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