VulnerabilityPublished 3 Nov 2026

CVE-2026-99266: Linux kernel · io_uring/zcrx: fix buffer offsets in areas above 4GB

Source GCVE Database

Authoritative record:CVE-2026-99266· High

Not known to be exploited : upgrade to 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 or 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b soon.

Data as of 3 Nov 2026, 13:15 UTC

Severity

High

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

Thin evidence

One scorer or none

Patch: Available – fixed in 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7, 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b

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-fpm3-962w-m24h

What to do

Upgrade Linux kernel to 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 or 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 11ed914bbf948c4a37248f2876973ac18014056d, < 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7	Fixed in 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7
LinuxLinux	Affected ≥ 11ed914bbf948c4a37248f2876973ac18014056d, < 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b	Fixed in 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b
LinuxLinux	Affected =6.15	Fixed in–

Description

A vulnerability in the Linux kernel's io_uring subsystem affects buffer offset calculations for areas above 4GB. The flaw causes the completion queue entry (CQE) to point to incorrect buffer data, potentially leading to reading wrong data and returning a buffer that the application does not own.

References

Community reviews

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