CVE-2026-89745: Linux kernel · debugfs: Fix lockdown check for mmap_prepare
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 9% 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 has been implemented in the Linux kernel to update the lockdown check for mmap_prepare. Users should apply the official kernel updates that include this fix. Since this is a kernel-level fix, upgrading to a patched kernel version is the recommended remediation.
Description
A vulnerability in the Linux kernel's debugfs lockdown check was fixed by updating the check to cover both mmap and mmap_prepare file operations. This issue arose because the kernel transitioned relayfs file operations from mmap to mmap_prepare, but the lockdown check was not updated accordingly, potentially allowing debugfs to be unlocked when it should be locked in integrity mode. The fix ensures comprehensive lockdown coverage during this transition.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89745 (opens in a new tab)
- git.kernel.org/stable/c/e7f6a6b5741d16fdac7adaecbe0fa52ae756f208 (opens in a new tab)
- git.kernel.org/stable/c/f81808de37338aac8e167f99bfae647b1b835c70 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89745 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89745 (opens in a new tab)
- git.kernel.org/linus/f81808de37338aac8e167f99bfae647b1b835c70 (opens in a new tab)