NanaZip: Heap out-of-bounds read in NanaZip AVB property descriptor parser via unsigned integer underflow

published 2026-06-12 4 mo ago modified 2026-10-26 14 d ago also EUVD-2026-36506

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits: 0; none known

NanaZip is the 7-Zip derivative intended for the modern Windows experience. From version 3.0.1000.0 to before version 6.0.1698.0, a heap out-of-bounds read exists in the Android Verified Boot (AVB) vbmeta image parser in NanaZip (via the upstream 7-Zip AvbHandler). An unsigned integer underflow in a bounds check allows an attacker-controlled value_num_bytes field to pass validation, causing AddNameToString to read up to ~4 GiB past the end of a 64 KiB heap buffer. This causes a deterministic crash (denial of service) when opening a crafted .avb or .img file. This issue has been patched in stable version 6.0.1698.0 and preview version 6.5.1742.0.

Patch / fix

fixed in 1

m2team nanazip 6.0.1698.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-12)

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/M2Team/NanaZip/security/advisories/GHSA-mqqj-crf3-6q37 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L

Affected products

M2Team NanaZip

Classification

Weakness

CWE-125 Out-of-bounds Read
CWE-191 Integer Underflow (Wrap or Wraparound)

References

github.com /M2Team/NanaZip/security/advisories/GHSA-mqqj-crf3-6q37
exploit

Sources

CVE List CVE-2026-47222
NVD CVE-2026-47222

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary