CVE-2026-55392 PUBLISHED

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

Assigner: VulnCheck
Reserved: 16.06.2026 Published: 18.06.2026 Updated: 18.06.2026

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.

CVSS Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 6.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Local	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	Active

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS Score: 5.5

Attack Vector	Local	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	Required	Availability Impact	High

CVSS 3.1

Product Status

Vendor	nilfs-dev
Product	nilfs-utils
Versions	Default: unaffected affected from 0 to 2.3.0 (incl.) Version 26efb5daff0757365101035145331b0a5a85d9d9 is unaffected

CVE-2026-55392 PUBLISHED

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

Metrics

Product Status

Credits

References

Problem Types