CVE-2026-80855: Linux kernel · fuse: fix invalidate lock leak on open O_TRUNC DAX failure
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 13:47 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation evidence
Disclosed: evidence found.
CVE published 4 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 address this issue by ensuring the lock is always released on error paths. Users should apply the official kernel update containing this fix once available. Patch status is not explicitly confirmed in the provided data; check the vendor advisory for current remediation guidance.
Description
In the Linux kernel, the following vulnerability has been resolved: fuse: fix invalidate lock leak on open O_TRUNC DAX failure fuse_open() takes filemap_invalidate_lock() for a DAX truncate (dax_truncate = true) and releases it before the out_inode_unlock label. But when fuse_dax_break_layouts() fails, the goto out_inode_unlock skips the unlock and leaks the rwsem, so any later fault or truncate on the file stalls on the stale lock. fuse_dax_break_layouts() can fail with -ERESTARTSYS when a signal interrupts the wait for busy DAX pages to drain: open("file", O_RDWR | O_TRUNC) └─ fuse_open() ├─ filemap_invalidate_lock() # dax_truncate └─ fuse_dax_break_layouts() └─ dax_break_layout() └─ wait_page_idle() # TASK_INTERRUPTIBLE └─ fuse_wait_dax_page() # unlock, schedule, re-lock └─ signal → -ERESTARTSYS goto out_inode_unlock # <- lock leaked Fix this by moving filemap_invalidate_unlock() below the label so that all error paths release the lock, and rename the label to out_unlock as it now covers more than just the inode lock.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80855 (opens in a new tab)
- git.kernel.org/stable/c/1b04d80a27d317064cce2307472f5bef9975bc50 (opens in a new tab)
- git.kernel.org/stable/c/1d3e701cda2f41d48aa721b3ebefbe0fbf8d74da (opens in a new tab)
- git.kernel.org/stable/c/7288c279ddbd654a06c82118c1a3f5570c1807f0 (opens in a new tab)
- git.kernel.org/stable/c/776e85fda752f9a15e0f82dec42ecacd12a9bd94 (opens in a new tab)
- git.kernel.org/stable/c/a61524da59a2f5ac9c8de23ff98b30da769ab144 (opens in a new tab)
- git.kernel.org/stable/c/a927f1867e61b78f39f9da0bbba3c98c2ca151fe (opens in a new tab)
- git.kernel.org/stable/c/dcf30a56624c2a0cfab1bada5b1ca8cc0c02f010 (opens in a new tab)
- git.kernel.org/stable/c/e981474d7bf1457da12404e169ea147d2c8ecea7 (opens in a new tab)
- ubuntu.com/security/CVE-2026-80855 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80855 (opens in a new tab)
- git.kernel.org/linus/a927f1867e61b78f39f9da0bbba3c98c2ca151fe (opens in a new tab)