CVE-2026-55780: DoS

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.

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EPSS — Exploit Prediction

0.0011

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-248 CWE-248

CWE-400 Uncontrolled Resource Consumption

References

Other References

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

Frequently Asked Questions

What is CVE-2026-55780? +

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.

How do I check if I'm vulnerable to CVE-2026-55780? +

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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