# CVE-2026-47223: M2Team NanaZip heap out-of-bounds read in AVB vbmeta parser

Source: https://junglewise.ai/threats/cve-2026-47223-m2team-nanazip-heap-out-of-bounds-read-in-avb-vbmeta-parser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-12. Updated: 2026-06-12  
License: CC BY 4.0 with a link back

CVE-2026-47223 · Severity: medium · CVSS 5.4 · Published 2026-06-12

NanaZip is a file archiver for Windows based on 7-Zip. A security flaw in how it handles Android Verified Boot (AVB) image files allows an attacker to crash the application by providing a specially crafted file. This could lead to a denial of service where the user is unable to open certain archives or the application stops responding.

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

## Quick answers

**Is CVE-2026-47223 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-47223 being exploited in the wild.

**How severe is CVE-2026-47223?** Medium severity, with a CVSS score of 5.4, published 12 June 2026.

**Which products and versions are affected?** M2Team NanaZip 3.0.1000.0 to 6.0.1698.0.

**Is there a fix for CVE-2026-47223?** 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-2026-47223 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-47223?** 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 heap out-of-bounds read exists in the Android Verified Boot (AVB) vbmeta image parser (AvbHandler) due to a 32-bit unsigned integer overflow. Specifically, in the bounds check 'pos + ht.salt_len > descSize', an attacker can provide a large 'salt_len' value that causes the addition to wrap around to a small value, bypassing the validation. This leads to a 'memcpy' operation in 'CByteBuffer::CopyFrom' that attempts to read up to 4 GiB from a heap buffer that is typically only 64 KiB. While the primary impact is a deterministic application crash (DoS) upon hitting unmapped memory, it could theoretically lead to limited information disclosure of adjacent heap memory. The vulnerability is reachable via network delivery of a crafted file and requires minimal user interaction (opening the file). The issue is fixed in stable version 6.0.1698.0 and preview version 6.5.1742.0.

## Affected products

- M2Team NanaZip 3.0.1000.0 to 6.0.1698.0

## Timeline

- 2026-05-18: advisory: GitHub Security Advisory published by M2Team
- 2026-06-12: disclosed: CVE published to NVD

## References

- [https://github.com/M2Team/NanaZip/security/advisories/GHSA-qhc5-mh6j-4g75](https://github.com/M2Team/NanaZip/security/advisories/GHSA-qhc5-mh6j-4g75)

## Related threats

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- [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)
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- [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)