CVE Catalog

CVE-2026-53320

MediumCVSS 5.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.12%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel, a vulnerability was found in the nilfs2 filesystem where nilfs_ioctl_mark_blocks_dirty() fails to reject a zero bd_oblocknr value. An attacker can send a crafted ioctl request with bd_oblocknr set to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block, triggering a WARN_ON(ret == -ENOENT).

Risk Assessment

The risk is the potential for system panic or disruption by sending a specially crafted ioctl request, leading to denial of service (DoS) on systems using nilfs2.

Recommendation

Immediately update the Linux kernel to a version containing the fix that rejects ioctl requests with bd_oblocknr equal to 0. If an update is not possible, restrict access to the ioctl interface for untrusted users.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty() nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks by comparing it with the current block number bd_blocknr. If they differ, the block is considered dead and skipped. However, bd_oblocknr should never be 0 since block 0 typically stores the primary superblock and is never a valid GC target block. A corrupted ioctl request with bd_oblocknr set to 0 causes the comparison to incorrectly match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering the WARN_ON(ret == -ENOENT). Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the beginning of each iteration. [ryusuke: slightly modified the commit message and comments for accuracy]

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