CVE-2026-89766: Linux kernel · pidfd: hold exec_update_lock around namespace ioctl
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 12:55 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 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 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther 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 is available that holds the exec_update_lock during the ptrace access check and namespace lookup in pidfd_ioctl(), aligning behavior with procfs. Users should apply the official kernel updates that include this fix to resolve the vulnerability.
Description
A vulnerability in the Linux kernel's pidfd ioctl handling was resolved by ensuring the exec_update_lock is held during namespace ioctl operations. Without this lock, a caller could bypass access checks and read namespace information after the target process changed credentials via execve(), potentially accessing data it should be denied. The fix aligns pidfd behavior with the procfs namespace handling by holding the lock during the ptrace access check and namespace lookup.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89766 (opens in a new tab)
- git.kernel.org/stable/c/9688a46802939da28f00cb40e8129615d5d4af39 (opens in a new tab)
- git.kernel.org/stable/c/cf24ce48d60225fdbee68ed2058763a1fd172ff3 (opens in a new tab)
- git.kernel.org/stable/c/e89318aa8629969e86548b05e7c19283af3f0efb (opens in a new tab)
- ubuntu.com/security/CVE-2026-89766 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89766 (opens in a new tab)
- git.kernel.org/linus/9688a46802939da28f00cb40e8129615d5d4af39 (opens in a new tab)
- git.kernel.org/stable/c/bac2f1913a216677c2c220d7bb352dd0330065ca (opens in a new tab)