CVE-2026-42443: NanaZip: Integer divide-by-zero in NanaZip UFS inode offset calculation

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-12 · updated 2026-10-26
Weakness: CWE-369

Description

NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, an integer divide-by-zero exists in the UFS/UFS2 filesystem image parser in NanaZip. The vulnerability is triggered when opening a crafted UFS image where the superblock field fs_ipg (inodes per cylinder group) is set to zero. The parser uses this attacker-controlled value as a divisor without validation, causing an immediate hardware trap and process crash. This vulnerability is fixed in 6.0.1698.0.

Affected products

M2Team NanaZip: from 5.0.1252.0 before 6.0.1698.0 — fixed in 6.0.1698.0

How to fix

Upgrade to a fixed version: M2Team NanaZip 6.0.1698.0. Check the vendor advisory for mitigations.

References

https://github.com/M2Team/NanaZip/security/advisories/GHSA-3x2h-gqqw-g3gm

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