CVE-2026-80856

Description

In the Linux kernel, the following vulnerability has been resolved: fuse: fix invalidate lock leak on setattr writeback failure fuse_do_setattr() takes filemap_invalidate_lock() for a DAX truncate (fault_blocked = true) and releases it at the out:/error: labels. But when a writeback flush is also needed, a write_inode_now() failure returns directly and leaks the lock, so any later fault or truncate on the file stalls on the stale rwsem. For example, truncate(2) on a setuid file reaches fuse_do_setattr() with both ATTR_SIZE and ATTR_MODE set: truncate(2) └─ do_truncate() ├─ dentry_needs_remove_privs() # S_ISUID └─ notify_change() # KILL_SUID -> ATTR_MODE └─ fuse_setattr() # no killpriv: │ # ia_valid |= ATTR_MODE └─ fuse_do_setattr() ├─ filemap_invalidate_lock() # IS_DAX && is_truncate └─ write_inode_now() # is_wb && ATTR_MODE └─ if (err) # e.g. daemon -> -EIO return err # <- lock leaked Fix this by adding an unlock label that releases the lock before returning the error, and use it for the fuse_dax_break_layouts() failure path as well.

Is your site exposed to CVE-2026-80856?

Run a free security scan — no signup, results in seconds.

EPSS — Exploit Prediction

0.0017

Probability of exploitation

0.06%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/03cfeeb135428fa83f0791d3f8f94d9298cae695 https://git.kernel.org/stable/c/1758730d9eaa3c06cf415c3446d9f6eed9ed3eed https://git.kernel.org/stable/c/8f14906ce9103ab8f2f1ebda45935a0d61b9d763 https://git.kernel.org/stable/c/92588d187ba4697a322e7aefe5d9e538a87d1cd2 https://git.kernel.org/stable/c/9afeca0d569c9fc89d758fe7a9339d1e8afb1546 https://git.kernel.org/stable/c/dd278d954c0e96a9cbd3cc491e07b8267d25f8d5 https://git.kernel.org/stable/c/e8457ebfd77a46e8d1210e8888ea914ad064558e https://git.kernel.org/stable/c/ea9fea370b8de4ffd72e0ef89550415c15637787

Frequently Asked Questions

What is CVE-2026-80856? +

In the Linux kernel, the following vulnerability has been resolved: fuse: fix invalidate lock leak on setattr writeback failure fuse_do_setattr() takes filemap_invalidate_lock() for a DAX truncate (fault_blocked = true) and releases it at the out:/error: labels. But when a writeback flush is also needed, a write_inode_now() failure returns directly and leaks the lock, so any later fault or truncate on the file stalls on the stale rwsem. For example, truncate(2) on a setuid file reaches fuse_do_setattr() with both ATTR_SIZE and ATTR_MODE set: truncate(2) └─ do_truncate() ├─ dentry_needs_remove_privs() # S_ISUID └─ notify_change() # KILL_SUID -> ATTR_MODE └─ fuse_setattr() # no killpriv: │ # ia_valid |= ATTR_MODE └─ fuse_do_setattr() ├─ filemap_invalidate_lock() # IS_DAX && is_truncate └─ write_inode_now() # is_wb && ATTR_MODE └─ if (err) # e.g. daemon -> -EIO return err # <- lock leaked Fix this by adding an unlock label that releases the lock before returning the error, and use it for the fuse_dax_break_layouts() failure path as well.

How do I check if I'm vulnerable to CVE-2026-80856? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.