Vulnerability · Published Jul 10, 2026 · Assigned by GitHub_M

CVE-2026-55780NanaZip: Uncaught exception / unbounded allocation in NanaZip .NET single-file Extract() via unvalidated entry Size

Low 2.4

In plain English

A low-severity uncontrolled resource consumption in NanaZip from M2Team. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities).

Severity (CVSS 4.0)2.4Low

Exploit odds (30 days)0.6%top 53.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

NanaZip is the 7-Zip derivative intended for the modern Windows experience. Prior to 6.5.1749.0, NanaZip's .NET single-file bundle handler in NanaZip.Codecs.Archive.DotNetSingleFile.cpp sizes its extraction buffer from the bundle entry Size field, which is only checked for sign and is not validated against the real file size. A crafted bundle can cause an attacker-chosen allocation inside Extract, where std::bad_alloc or std::length_error can escape across the COM STDMETHODCALLTYPE boundary and crash the process. This issue is fixed in version 6.5.1749.0.

Affected products (as reported)

Vendor	Product	Versions
M2Team	NanaZip	< 6.5.1749.0

Weakness: CWE-248, CWE-400 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

https://github.com/M2Team/NanaZip/security/advisories/GHSA-ppm9-5267-rq72 x_refsource_CONFIRM
https://github.com/M2Team/NanaZip/commit/ad62e3b4970b9f01e924c99094d6fed7a42f849a x_refsource_MISC
https://github.com/M2Team/NanaZip/releases/tag/6.5.1749.0 x_refsource_MISC