Vulnerability · Published Jul 10, 2026 · Assigned by GitHub_M

CVE-2026-55783NanaZip: NULL pointer dereference in Extract() of all seven NanaZip custom archive handlers when extracting/testing the whole archive

Low 2.4

In plain English

A low-severity null pointer dereference in NanaZip from M2Team. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities).

Severity (CVSS 4.0)2.4Low

Exploit odds (30 days)0.2%top 93.1% 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 seven in-house IInArchive handlers in NanaZip.Codecs unconditionally dereference the caller-supplied Indices array inside Extract when the archive engine signals extract everything by passing Indices as NULL and NumItems as 0xFFFFFFFF. This causes a NULL pointer dereference in the standard Test archive or Extract all code path for WebAssembly, ElectronAsar, Zealfs, Romfs, Ufs, Littlefs, and DotNetSingleFile archives, resulting in a process crash. 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-476 · 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-q67r-9cfh-xc29 x_refsource_CONFIRM
https://github.com/M2Team/NanaZip/commit/5d74d90b737ac7096e5d944a5a3070c5c6a8f894 x_refsource_MISC
https://github.com/M2Team/NanaZip/releases/tag/6.5.1749.0 x_refsource_MISC