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    CVE-2026-82450

    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.

    Published:Aug 29, 2026
    Last Modified:Aug 31, 2026
    EPS:Aug 29, 2026
    EPSS Score:0.00572
    CVSS Score:8.8

    Affected Products

    Vendor
    Bookstackapp
    Product
    Bookstack

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-1 Accessing Functionality Not Properly Constrained by ACLs

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    CVE-2022-40690 (CVSS 5.4) — Cross-site scripting vulnerability in BookStack versions prior to v22.09 allows a remote authenticated attacke…
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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High