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CVE-2026-82450
8.7 HIGH
- CVSS version (CVSS): 4.0
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Attack Requirement (AT): None (N)
- Privileges Required (PR): Low (L)
- User Interaction (UI): None (N)
- Vulnerable System Impact Confidentiality (VC): High (H)
- Vulnerable System Impact Integrity (VI): High (H)
- Vulnerable System Impact Availability (VA): High (H)
- Subsequent System Impact Confidentiality (SC): None (N)
- Subsequent System Impact Integrity (SI): None (N)
- Subsequent System Impact Availability (SA): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Attack Requirement (MAT): None (N)
- Modified Privileges Required (MPR): Low (L)
- Modified User Interaction (MUI): None (N)
- Modified Vulnerable System Impact Confidentiality (MVC): High (H)
- Modified Vulnerable System Impact Integrity (MVI): High (H)
- Modified Vulnerable System Impact Availability (MVA): High (H)
- Modified Subsequent System Impact Confidentiality (MSC): Negligible (N)
- Modified Subsequent System Impact Integrity (MSI): Negligible (N)
- Modified Subsequent System Impact Availability (MSA): Negligible (N)
- Safety (S): Not Defined (X)
- Automatable (AU): Not Defined (X)
- Recovery (R): Not Defined (X)
- Value Density (V): Not Defined (X)
- Vulnerability Response Effort (RE): Not Defined (X)
- Provider Urgency (U): Not Defined (X)
- Confidentiality Req. (CR): Not Defined (X)
- Integrity Req. (IR): Not Defined (X)
- Availability Req. (AR): Not Defined (X)
- Exploit Maturity (E): Not Defined (X)
Activity log
- Created suggestion
BookStack before 26.05.4 Remote Code Execution via Book Cover
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.
References
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Patch Commit patch
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VulnCheck Advisory: BookStack before 26.05.4 Remote Code Execution via Book Cover third-party-advisory
Affected products
bookstack
- <26.05.4
Package maintainers
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@savyajha Savyasachee Jha <savya.jha@hawkradius.com>