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TI-2026-39963 Aliases CVE-2026-55392GHSA-f559-vgh2-9hj6

NILFS utilities - Undefined Behavior and Out-of-Memory via Unvalidated s_log_block_size

Priority LOW 29CWE-1284Published · Updated

Key facts

Attack vector
Local
Privileges required
None
User interaction
Active
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

NILFS utilities through 2.3.0, fixed in commit 26efb5d, nilfs_sb_is_valid() function fails to validate s_log_block_size field in NILFS2 superblock before bit-shift operations. Attackers supplying crafted NILFS2 images trigger undefined behavior through oversized shifts or out-of-memory conditions, crashing tools like nilfs-tune and dumpseg.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00151 4th percentileScored 2026-11-07
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nilfs-devnilfs-utilsup to 2.3.0—Patch availableCNA
  • nilfs-utils Vendornilfs-dev Affected up to 2.3.0 Fixed in — Patch available CNA

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55392
  2. 2026-10-03 Alias added: GHSA-f559-vgh2-9hj6

References

Patch 1

Other 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences