CVE-2026-74359

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

configfs_lookup(): don't leave ->s_dentry dangling on failure

Normally ->s_dentry is cleared when dentry it's pointing to becomes

negative (on eviction, realistically). However, that only happens

if dentry gets to be positive in the first place; in case of inode

allocation failure dentry never becomes positive, so ->d_iput()

is not called at all.

We do part of what normally would've been done by configfs_d_iput()

(dropping the reference to configfs_dirent) manually, but we do

not clear ->s_dentry there. Sloppy as it is, it does not matter in

case of configfs_create_{dir,link}() - there configfs_dirent does

not survive dropping the sole reference to it.

However, for configfs_lookup() it *does* survive, with a dangling

pointer to soon to be freed dentry sitting it its ->s_dentry.

Subsequent getdents(2) in that directory will end up dereferencing

that pointer in order to pick the inode number. Use after free...

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Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References