# CVE-2026-44215: M2Team NanaZip heap out-of-bounds write in UFS parser

Source: https://junglewise.ai/threats/cve-2026-44215-m2team-nanazip-heap-out-of-bounds-write-in-ufs-parser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-12. Updated: 2026-05-14  
License: CC BY 4.0 with a link back

CVE-2026-44215 · Severity: medium · CVSS 4.4 · Published 2026-05-12

NanaZip is an open-source file archiver used to compress and extract various file formats. A security flaw in how it handles UFS filesystem images allows a specially crafted file to corrupt the application's memory when opened. This could lead to the program crashing or potentially allow more sophisticated attacks, though it requires a user to manually open the malicious file.

Technologies: [M2Team NanaZip](https://junglewise.ai/threats/technologies/nanazip). Vendors: [M2Team](https://junglewise.ai/threats/vendors/m2team).

## Quick answers

**Is CVE-2026-44215 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-44215 being exploited in the wild.

**How severe is CVE-2026-44215?** Medium severity, with a CVSS score of 4.4, published 12 May 2026.

**Which products and versions are affected?** M2Team NanaZip 5.0.1252.0 to 6.0.1698.0.

**Is there a fix for CVE-2026-44215?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-44215 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-44215?** Check whether you run M2Team NanaZip at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A one-byte heap out-of-bounds null write exists in the UFS/UFS2 filesystem image parser within NanaZip's GetAllPaths function. The vulnerability is caused by a failure to verify that the name length (d_namlen) plus a null terminator fits within the directory record length (d_reclen) or the allocated buffer. An attacker can trigger this by providing a crafted UFS image where a directory entry is placed at the end of a block with a maximum name length value. This allows a null byte to be written up to 254 bytes past the heap allocation boundary. While modern Windows mitigations (CFG, CET) make exploitation difficult, the flaw can cause a denial of service or be used as a primitive for further heap corruption. The issue is fixed in version 6.0.1698.0.

## Affected products

- M2Team NanaZip 5.0.1252.0 to 6.0.1698.0

## Timeline

- 2026-04-27: advisory: GitHub Security Advisory published by MouriNaruto
- 2026-05-12: disclosed: CVE-2026-44215 published

## References

- [https://github.com/M2Team/NanaZip/security/advisories/GHSA-44wh-7gc3-w936](https://github.com/M2Team/NanaZip/security/advisories/GHSA-44wh-7gc3-w936)

## Related threats

- [NanaZip SquashfsHandler heap out-of-bounds read and information disclosure](https://junglewise.ai/threats/cve-2026-54616-nanazip-squashfshandler-heap-out-of-bounds-read-and-information)
- [M2Team NanaZip NULL pointer dereference in NanaZip.Codecs archive handlers](https://junglewise.ai/threats/cve-2026-55783-m2team-nanazip-null-pointer-dereference-in-nanazip-codecs-archive)
- [M2Team NanaZip uncontrolled memory allocation in WebAssembly handler](https://junglewise.ai/threats/cve-2026-55782-m2team-nanazip-uncontrolled-memory-allocation-in-webassembly)
- [M2Team NanaZip memory exhaustion in UFS and FFS image handler](https://junglewise.ai/threats/cve-2026-55781-m2team-nanazip-memory-exhaustion-in-ufs-and-ffs-image-handler)
- [M2Team NanaZip uncaught exception in .NET single-file handler](https://junglewise.ai/threats/cve-2026-55780-m2team-nanazip-uncaught-exception-in-net-single-file-handler)