CVE-2026-82450

Summary

BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests.

Affected Software

VendorProductVersion RangeStatus
bookstackappbookstack0 < 26.05.4affected

Weaknesses

  • CWE-434: Unrestricted Upload of File with Dangerous Type

References