CVE-2026-89723: Linux kernel · nilfs2: fix slab-out-of-bounds in nilfs_direct_propagate after truncation
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation 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 explicitly deletes the residual intermediate node block during the B-tree to direct mapping transformation in NILFS2. Users should apply the official Linux kernel patches that address this issue. Since this is a kernel-level vulnerability, updating to patched kernel versions is the recommended remediation.
Description
A slab-out-of-bounds vulnerability in the Linux kernel's NILFS2 filesystem was fixed. The issue occurred when a node block below the B-tree root was not deleted after truncation, leading to improper handling in nilfs_direct_propagate(). This caused out-of-bounds memory access due to treating B-tree nodes as direct mapping data blocks. The fix involves explicitly deleting the leftover intermediate node block during mapping transformation.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89723 (opens in a new tab)
- git.kernel.org/stable/c/28362e8ce51377afdec1782e661e808328a10514 (opens in a new tab)
- git.kernel.org/stable/c/448636c745a3f3b8582a0b8ce718c890a11c0fa9 (opens in a new tab)
- git.kernel.org/stable/c/45662dedb8f272ef7f16e69f13424c4bd0399240 (opens in a new tab)
- git.kernel.org/stable/c/5d3783c451a546373662ee11ec17019273e68034 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89723 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89723 (opens in a new tab)
- git.kernel.org/linus/45662dedb8f272ef7f16e69f13424c4bd0399240 (opens in a new tab)