CVE-2026-99263: Linux kernel · io_uring/poll: avoid retry wakeup loss when dropping ownership
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in eb2a50d8235e4580fea9aa20f3fbe1a002c38cb1 : update Linux kernel when convenient.
Data as of 3 Nov 2026, 12:13 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
Thin evidence
One scorer or none- Patch
- Available – fixed in eb2a50d8235e4580fea9aa20f3fbe1a002c38cb1, d1f6850086ac6f8b0fa44fb19aa2a468c73ee071, afa407c02f3aa0fd872f86c9bf1b34502e0fa8f0 +5
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.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Red Hatredhat/kernelpkg:rpm/redhat/kernelOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This issue has been fixed in Linux kernel versions 5.16, 6.1, and later. Users should upgrade to these or later versions to remediate the vulnerability. No additional mitigation is required once patched.
Description
A vulnerability in the Linux kernel's io_uring polling mechanism could cause a stall in processing requests due to a wakeup retry flag being lost when dropping ownership. This issue has been fixed by changing the atomic operation to ensure no wake-ups are missed.
References
- git.kernel.org/stable/c/d1f6850086ac6f8b0fa44fb19aa2a468c73ee071 (opens in a new tab)
- git.kernel.org/stable/c/41fae2e9e1fa3bee86aee0a25ba90e59ce5024bf (opens in a new tab)
- git.kernel.org/stable/c/4ef685b8505615729d75c875f52822238bf76ca6 (opens in a new tab)
- git.kernel.org/stable/c/afa407c02f3aa0fd872f86c9bf1b34502e0fa8f0 (opens in a new tab)
- git.kernel.org/stable/c/eb2a50d8235e4580fea9aa20f3fbe1a002c38cb1 (opens in a new tab)
- git.kernel.org/stable/c/521e8a65e9b45532295ba1082ef12be6e80c173b (opens in a new tab)