CVE-2026-53244

Description

In the Linux kernel, the following vulnerability has been resolved: VFS: fix possible failure to unlock in nfsd4_create_file() atomic_create() in fs/namei.c drops the reference to the dentry when it returns an error. This behaviour was imported into dentry_create() so that it will drop the reference if an error is returned from atomic_create(), though not if vfs_create() returns an error (in the case where ->atomic_create is not supported). The caller - nfsd4_create_file() - is made aware of this by checking path->dentry, which will either be a counted reference to a dentry, or an error pointer. However the change to use start_creating()/end_creating() (which landed shortly before the dentry_create() change landed, though was likely developed around the same time) means that nfsd4_create_file() *needs* a valid dentry so that it can unlock the parent. The net result is that if NFSD exports a filesystem which uses ->atomic_create, and if a call to ->atomic_create returns an error, then nfsd4_create_file() will pass an error pointer to end_creating() and the parent will not be unlocked. Fix this by changing dentry_create() to make sure path->dentry is always a valid dentry, never an error-pointer. The actual error is already returned a different way. Note that if ->atomic_create() returns a different dentry (which may not be possible in practice) we are guaranteed (because it is only ever provided by d_spliace_alias()) that it will have the same d_parent and so it will have the same effect when passed to end_creating().

CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0036

Probability of exploitation

0.28%

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/e824bbd4d224cce4b5fb59cc9dcd3447fe0b7e44 https://git.kernel.org/stable/c/ee1f40759a50b1800c98c1c369afd5b3e44ad987

Frequently Asked Questions

What is CVE-2026-53244? +

In the Linux kernel, the following vulnerability has been resolved: VFS: fix possible failure to unlock in nfsd4_create_file() atomic_create() in fs/namei.c drops the reference to the dentry when it returns an error. This behaviour was imported into dentry_create() so that it will drop the reference if an error is returned from atomic_create(), though not if vfs_create() returns an error (in the case where ->atomic_create is not supported). The caller - nfsd4_create_file() - is made aware of this by checking path->dentry, which will either be a counted reference to a dentry, or an error pointer. However the change to use start_creating()/end_creating() (which landed shortly before the dentry_create() change landed, though was likely developed around the same time) means that nfsd4_create_file() *needs* a valid dentry so that it can unlock the parent. The net result is that if NFSD exports a filesystem which uses ->atomic_create, and if a call to ->atomic_create returns an error, then nfsd4_create_file() will pass an error pointer to end_creating() and the parent will not be unlocked. Fix this by changing dentry_create() to make sure path->dentry is always a valid dentry, never an error-pointer. The actual error is already returned a different way. Note that if ->atomic_create() returns a different dentry (which may not be possible in practice) we are guaranteed (because it is only ever provided by d_spliace_alias()) that it will have the same d_parent and so it will have the same effect when passed to end_creating(). It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-53244? +

CVE-2026-53244 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0036, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-53244? +

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.