CVE Catalog

CVE-2025-40190

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.16%

6th percentile - higher than 6% of all known CVEs

Summary

In the Linux kernel, the ext4 filesystem lacks protection against EA inode refcount underflow. This can lead to underflow and filesystem errors.

Risk Assessment

The organization may experience ext4 filesystem corruption and critical errors, potentially leading to data loss or system instability.

Recommendation

It is recommended to update the Linux kernel to a version containing the fix that validates the refcount before modification.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ext4: guard against EA inode refcount underflow in xattr update syzkaller found a path where ext4_xattr_inode_update_ref() reads an EA inode refcount that is already <= 0 and then applies ref_change (often -1). That lets the refcount underflow and we proceed with a bogus value, triggering errors like: EXT4-fs error: EA inode <n> ref underflow: ref_count=-1 ref_change=-1 EXT4-fs warning: ea_inode dec ref err=-117 Make the invariant explicit: if the current refcount is non-positive, treat this as on-disk corruption, emit ext4_error_inode(), and fail the operation with -EFSCORRUPTED instead of updating the refcount. Delete the WARN_ONCE() as negative refcounts are now impossible; keep error reporting in ext4_error_inode(). This prevents the underflow and the follow-on orphan/cleanup churn.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS