CVE-2026-93268: Linux kernel · ext4: skip extra isize expansion during mount to prevent deadlock
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 14:05 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% 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 24 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.
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: skip extra isize expansion during mount to prevent deadlock ext4_try_to_expand_extra_isize() is called from __ext4_mark_inode_dirty() while holding an active jbd2 handle. During mount (!SB_ACTIVE), the expand path may move xattrs to external blocks and release ea_inodes via iput(). When !SB_ACTIVE, iput() calls write_inode_now() which acquires s_writepages_rwsem, creating a circular lock dependency: s_writepages_rwsem --> jbd2_handle --> xattr_sem --> s_writepages_rwsem This can be triggered via: ext4_process_orphan() -> ext4_truncate() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() or: ext4_evict_inode() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() Skip expansion when !SB_ACTIVE. This is a minor loss of functionality (extra isize won't grow for these inodes during mount), which e2fsck can resolve later if needed.
References
- ubuntu.com/security/CVE-2026-93268 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-93268 (opens in a new tab)
- git.kernel.org/stable/c/9c3469377b1d8caba6bec6ef3c460810bbfb02cc (opens in a new tab)
- git.kernel.org/stable/c/7ba09330d9ea6e996228316719eae812d7e04983 (opens in a new tab)
- git.kernel.org/stable/c/2fb8ff81659a57c42bb7b49e8339a2be2a318ef8 (opens in a new tab)
- git.kernel.org/stable/c/1dd4882dbdc8bfdf2182fa388883c143fac0902a (opens in a new tab)
- git.kernel.org/stable/c/7ace189b9ea79cf78df9c32b940ce12735f9459a (opens in a new tab)
- git.kernel.org/stable/c/7461c60b9c6a839b13ad4c3490681a0cf5aa0637 (opens in a new tab)
- git.kernel.org/stable/c/c5e6434cc55f30220b228be237bb666351f9f4dd (opens in a new tab)
- git.kernel.org/stable/c/41897f1bcf4ace5f1f28d0be784b6f4f0e929641 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-93268.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)