CVE-2026-42444: NanaZip: Unbounded resource consumption in NanaZip littlefs parser via attacker-controlled BlockCount

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-770

Description

NanaZip is an open source file archive. From 5.0.1252.0 to before 6.0.1698.0, a denial-of-service vulnerability exists in the littlefs filesystem image parser in NanaZip. The handler's Open method reads BlockCount directly from the attacker-controlled superblock without any validation against the actual file size or any upper-bound ceiling, then iterates BlockCount times, allocating a file-path entry per iteration. A crafted 44-byte littlefs image with BlockCount = 0xFFFFFFFF causes ~4 billion heap allocations, exhausting available memory. 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

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