CVE-2026-89786: Linux kernel · ext4: fix out-of-bounds read in ext4_read_inline_dir()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 26 Oct 2026, 15:59 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 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 for this vulnerability has been implemented in the Linux kernel. Users and administrators should update to the patched kernel versions to remediate this issue. Since this is a kernel-level vulnerability, applying the official kernel updates from the vendor or distribution is the recommended mitigation. No additional workaround or temporary fix is indicated.
Description
A vulnerability in the Linux kernel's ext4 filesystem implementation allows an out-of-bounds read in the ext4_read_inline_dir() function. This occurs because the function can read directory entry headers beyond the end of its inline buffer, causing a slab-out-of-bounds read during directory iteration. The issue arises from a mismatch between the buffer size and the position space used for iteration, leading to unsafe memory access.
References
- ubuntu.com/security/CVE-2026-89786 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89786 (opens in a new tab)
- git.kernel.org/linus/9333cc809f0a89e001b814155a6cb8903a6274df (opens in a new tab)
- git.kernel.org/stable/c/1a1dea633b724a1c042dbcdb1fed27f410916688 (opens in a new tab)
- git.kernel.org/stable/c/36bf17bb90cdf7a623499b624b05acde4d2feef5 (opens in a new tab)
- git.kernel.org/stable/c/5fd20d4e50dd6e460b3ea8e4396f8553d4526f8f (opens in a new tab)
- git.kernel.org/stable/c/6702c7da86d8cdb88d0fc57166286e115ffeb8c0 (opens in a new tab)
- git.kernel.org/stable/c/9333cc809f0a89e001b814155a6cb8903a6274df (opens in a new tab)
- git.kernel.org/stable/c/b060861f662d4826dc700a1c3584243bb3474cfe (opens in a new tab)
- git.kernel.org/stable/c/d1e7c186555ad65554fd2f2b02f5a539aa35ae48 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89786.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)