VulnerabilityPublished 26 Oct 2026

CVE-2026-99096: Linux kernel · io_uring/register: don't exempt disabled rings from task restrictions

Source GCVE Database

Authoritative record:CVE-2026-99096· High

Not known to be exploited : upgrade to f55c240192ded562386de843bfa067671d2731d5 or 6da8f402e362b2f546e2efb7167fc9597aef6faf soon.

Data as of 26 Oct 2026, 16:31 UTC

Severity

High

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

Patch: Available – fixed in f55c240192ded562386de843bfa067671d2731d5, 6da8f402e362b2f546e2efb7167fc9597aef6faf

Exploitation evidence

Disclosed: evidence found.
CVE published 26 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.

ghsa-4xv2-crf6-2mgc

What to do

Upgrade Linux kernel to f55c240192ded562386de843bfa067671d2731d5 or 6da8f402e362b2f546e2efb7167fc9597aef6faf.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ ed82f35b926b2e505c14b7006473614b8f58b4f4, < f55c240192ded562386de843bfa067671d2731d5	Fixed in f55c240192ded562386de843bfa067671d2731d5
LinuxLinux	Affected ≥ ed82f35b926b2e505c14b7006473614b8f58b4f4, < 6da8f402e362b2f546e2efb7167fc9597aef6faf	Fixed in 6da8f402e362b2f546e2efb7167fc9597aef6faf
LinuxLinux	Affected =7.0	Fixed in–
Red Hatredhat/kernel`pkg:rpm/redhat/kernel`Other threats	Affected =7.0	Fixed in–

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

AI-suggested

A fix has been implemented in the Linux kernel to enforce register opcode restrictions on disabled rings that inherit restrictions from their creating task. Users should update to a kernel version that includes this fix.

Description

A vulnerability in the Linux kernel's io_uring subsystem allowed disabled rings to bypass task-specific register opcode restrictions. This could enable a task with restricted register opcodes to create a disabled ring, perform any register operation on it, and then enable the ring regardless of the allowed opcode set. The issue has been fixed by ensuring that disabled rings inheriting restrictions from their creating task continue to enforce those restrictions until enabled.

References

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