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

> Attackers can cause memory exhaustion and denial of service in NanaZip by providing a crafted littlefs image with an invalid block count.

- **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 May 2026
- **Updated:** 14 May 2026
- **Also known as:** GHSA-7hqh-mq57-wjmq

## What is CVE-2026-42444?

CVE-2026-42444 is a low-severity denial of service vulnerability in M2Team NanaZip, published on 12 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official 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.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-42444?

It affects 1 product.


Products: M2team Nanazip.

## How do I fix CVE-2026-42444?

No fix has been published for CVE-2026-42444 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-42444 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42444 exists.

## Other vulnerabilities in M2Team NanaZip

- [CVE-2026-26282](https://insights.sbomify.com/CVE-2026-26282/): NanaZip has DotNet Single file OOB Heap Read (medium 5.2)
- [CVE-2026-27709](https://insights.sbomify.com/CVE-2026-27709/): NanaZip .NET Single-File Manifest Parser Vulnerable to Out-of-Bounds Read via Unchecked RelativePathLength (medium 5.1)
- [CVE-2026-27710](https://insights.sbomify.com/CVE-2026-27710/): NanaZip .NET Single-File Parser Integer Underflow Leads to Unbounded Allocation (DoS) (medium 5.1)
- [CVE-2026-27711](https://insights.sbomify.com/CVE-2026-27711/): NanaZip UFS Archive Parser Memory Corruption via Unvalidated Directory Record Length (medium 5.1)
- [CVE-2026-27014](https://insights.sbomify.com/CVE-2026-27014/): NanZip has ROMFS Archive Infinite Loop / Stack Overflow (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42444 and fix it if it is affected.

What it is: CVE-2026-42444 is a low-severity denial of service vulnerability in M2Team NanaZip, published on 12 May 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42444 exists.

Affected product: M2Team NanaZip. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42444/ (Markdown: https://insights.sbomify.com/CVE-2026-42444/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42444
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42444
- OSV: https://osv.dev/vulnerability/CVE-2026-42444

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42444/
Summaries are generated and may contain mistakes; the official description above is the record.