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Description

A vulnerability in B1 Free Archiver v1.5.86 allows files extracted from downloaded archives to bypass Windows Mark of the Web (MotW) protections. When an archive is downloaded from the internet and extracted using B1 Free Archiver, the software fails to propagate the 'Zone.Identifier' alternate data stream to the extracted files. As a result, these files can be executed without triggering Windows Defender SmartScreen warnings or security prompts, enabling untrusted code execution without standard security restrictions.

PUBLISHED Reserved 2025-06-16 | Published 2026-04-29 | Updated 2026-04-30 | Assigner mitre

References

github.com/math69b/B1FREE/blob/main/B1 Free Archiver version exploit

b1.org/

github.com/math69b/B1FREE/blob/main/B1 Free Archiver version

cve.org (CVE-2025-50328)

nvd.nist.gov (CVE-2025-50328)

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