CVE-2026-53320: 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_obl

unknownCVE-2026-53320

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]

Details

Source: NVD Recent CVEs (US · database · site)
Severity: unknown
Published: 2026-06-26
Last updated: 2026-06-30
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-53320

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-533200.12% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 2% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53320	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownMultiple vulnerabilities in Debian LTS Linux kernel (July 10, 2026)cert-fr-avis
medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilitiescert-bund
mediumCVE-2026-53320: nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()msrc

Recent advisories for In the Linux

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of servicecert-bund · 2026-07-10
medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow unspecified attackcert-bund · 2026-07-10
medium[UPDATE] [medium] Linux Kernel: Multiple vulnerabilities allow denial of servicecert-bund · 2026-07-10
high[UPDATE] [high] Linux Kernel: Multiple vulnerabilitiescert-bund · 2026-07-10