CVE-2026-55783

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.

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Weakness Type (CWE)

CWE-476 CWE-476

References

Other References

https://github.com/M2Team/NanaZip/commit/5d74d90b737ac7096e5d944a5a3070c5c6a8f894 https://github.com/M2Team/NanaZip/releases/tag/6.5.1749.0 https://github.com/M2Team/NanaZip/security/advisories/GHSA-q67r-9cfh-xc29 https://github.com/M2Team/NanaZip/security/advisories/GHSA-q67r-9cfh-xc29

Frequently Asked Questions

What is CVE-2026-55783? +

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.

How do I check if I'm vulnerable to CVE-2026-55783? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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