VulnerabilityPublished 28 Oct 2026

CVE-2026-99130: Linux kernel · io_uring/cancel: don't spin on local work the task can't run

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in fddcf4c5321b3ea5f72166c3fd36a9d1c34f80c7 : update Linux kernel when convenient.

Data as of 28 Oct 2026, 10:58 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

Patch: Available – fixed in fddcf4c5321b3ea5f72166c3fd36a9d1c34f80c7, 3005459e0ddfcef0f555b6e81f672f2c49a1c0aa, 94d13387b96e50a4288f7bbdfe401189246a11a1

Exploitation evidence

Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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 Linux kernel to fddcf4c5321b3ea5f72166c3fd36a9d1c34f80c7, 3005459e0ddfcef0f555b6e81f672f2c49a1c0aa or 94d13387b96e50a4288f7bbdfe401189246a11a1.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 360cd42c4e95ff06d8d7b0a54e42236c7e7c187f, < fddcf4c5321b3ea5f72166c3fd36a9d1c34f80c7	Fixed in fddcf4c5321b3ea5f72166c3fd36a9d1c34f80c7
LinuxLinux	Affected ≥ 360cd42c4e95ff06d8d7b0a54e42236c7e7c187f, < 3005459e0ddfcef0f555b6e81f672f2c49a1c0aa	Fixed in 3005459e0ddfcef0f555b6e81f672f2c49a1c0aa
LinuxLinux	Affected ≥ 360cd42c4e95ff06d8d7b0a54e42236c7e7c187f, < 94d13387b96e50a4288f7bbdfe401189246a11a1	Fixed in 94d13387b96e50a4288f7bbdfe401189246a11a1
LinuxLinux	Affected =6.4	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/cancel: don't spin on local work the task can't run io_uring_cancel_generic() refuses to sleep while any ring on the exiting task's tctx has local work pending. It assumes the task is that ring's submitter and that the next io_uring_try_cancel_requests() pass will run the work. This does not hold for a ring that was still IORING_SETUP_R_DISABLED when the task got its tctx node from io_uring_create() or io_ringfd_register(). The submitter is set later by IORING_REGISTER_ENABLE_RINGS, possibly from another task, and only the submitter may run local work on an IORING_SETUP_DEFER_TASKRUN ring. To the exiting task the work stays pending forever, the loop never reaches schedule(), and the task trips the WARN_ON_ONCE() once and then spins in do_exit(). An unprivileged user can set this up at will by creating a disabled ring, having a child enable it and stop, posting to the ring with IORING_OP_MSG_RING and exiting with a request in flight that only the child can complete. The exiting thread burns a CPU until the child runs or dies, and with panic_on_warn set the WARN panics the kernel. Fix by skipping the sleep only when io_allowed_defer_tw_run() allows the task to run the work. This is reasonable since work it cannot run cannot complete any of its requests either, so nothing is lost by sleeping. Drop the WARN_ON_ONCE() since handing a disabled ring to another thread is a supported scenario, not a bug state.

References

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