# CVE-2026-54616: NanaZip: Heap out-of-bounds read in NanaZip SquashFS LZ4 decompressor via unchecked negative return value

> An attacker can cause an out-of-bounds read in NanaZip's SquashFS decompressor, potentially leaking heap memory or crashing the application via a crafted archive.

- **Severity:** High 7.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 20 Aug 2026
- **Updated:** 20 Aug 2026
- **Also known as:** GHSA-95x5-qvvm-hmfp

## What is CVE-2026-54616?

CVE-2026-54616 is a high-severity memory corruption vulnerability in M2Team NanaZip, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 1.0.88.0 until stable version 6.0.1698.0 and preview version 6.5.1742.0, the Lz4Decode function in NanaZip.Core/SevenZip/CPP/7zip/Archive/SquashfsHandler.cpp rejects only a zero return from LZ4_decompress_safe even though malformed input produces a negative error value. The negative int is converted to the unsigned SizeT destLen and then truncated into outBufWasWrittenSize, causing ReadBlock to trust an attacker-inflated _cachedUnpackBlockSize. During fragment extraction, an attacker-controlled inode Offset can make memcpy read beyond the _cachedBlock heap allocation and place adjacent heap contents in the extracted file, or crash the process. This issue is fixed in stable version 6.0.1698.0 and preview version 6.5.1742.0.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-54616?


## How do I fix CVE-2026-54616?

No fix has been published for CVE-2026-54616 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-54616 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54616 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54616 and fix it if it is affected.

What it is: CVE-2026-54616 is a high-severity memory corruption vulnerability in M2Team NanaZip, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, 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-2026-54616 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-2026-54616/ (Markdown: https://insights.sbomify.com/CVE-2026-54616/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54616
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54616
- OSV: https://osv.dev/vulnerability/CVE-2026-54616

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54616/
Summaries are generated and may contain mistakes; the official description above is the record.