CVE-2026-74400

Technical Description

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

bpf: fix crash in bpf_[set|remove]_dentry_xattr for negative dentries

bpf_set_dentry_xattr and bpf_remove_dentry_xattr BPF kfuncs attempt to

lock the inode of the supplied dentry without checking if it is

NULL. If a negative dentry is passed (e.g. from

security_inode_create), d_inode(dentry) returns NULL, and

inode_lock(inode) will cause a NULL pointer dereference.

Trivially fix this by adding a NULL check for inode before attempting

to lock it, returning -EINVAL if it is NULL.

Additionally, drop WARN_ON(!inode) in bpf_xattr_read_permission() and

bpf_xattr_write_permission(). These warnings could be triggered by

passing a negative dentry to bpf_get_dentry_xattr() or the _locked

variants of the xattr kfuncs, potentially causing a Denial of Service

on systems with panic_on_warn enabled. Instead, simply return -EINVAL.

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