CVE-2026-99096: Linux kernel · io_uring/register: don't exempt disabled rings from task restrictions
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 29 Oct 2026, 00:58 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
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.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther 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
A fix has been implemented to enforce register opcode restrictions on disabled rings that inherit restrictions from their creating task. Users should update to a Linux kernel version that includes this fix to prevent exploitation. No additional mitigation steps are indicated.
Description
A vulnerability in the Linux kernel's io_uring subsystem allowed tasks to bypass register opcode restrictions by creating disabled rings that were exempt from these restrictions until enabled. This flaw permitted a task with restricted register opcodes to create a disabled ring, perform any register opcode on it, and then enable the ring without proper permission checks. The issue has been fixed by marking rings that inherit restrictions from their creating task and enforcing opcode checks even while the ring is disabled.