CVE-2026-82450
BookStack before 26.05.4 Remote Code Execution via Book Cover
- State
- Published
- Severity
- 8.7 High
- Published
- Aug 29, 2026
- Updated
- Oct 8, 2026
- Reserved
- Aug 29, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-434 Unrestricted Upload of File with Dangerous Type
Affected Products
| Product | Versions |
|---|---|
bookstackbookstackapp |
|
References
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