Arbitrary file upload in BookStack - CVE-2020-5256
Published: March 9, 2020 / Updated: July 17, 2020
Vulnerability identifier: #VU30337
CSH Severity: High
CVSS v4.0: 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/E:U/U:Amber
CVE-ID: CVE-2020-5256
CWE-ID: CWE-434
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Dan Brown
Affected software:
BookStack
BookStack
Detailed vulnerability description
The vulnerability allows a remote authenticated user to execute arbitrary code.
BookStack before version 0.25.5 has a vulnerability where a user could upload PHP files through image upload functions, which would allow them to execute code on the host system remotely. They would then have the permissions of the PHP process. This most impacts scenarios where non-trusted users are given permission to upload images in any area of the application. The issue was addressed in a series of patches in versions 0.25.3, 0.25.4 and 0.25.5. Users should upgrade to at least v0.25.5 to avoid this vulnerability.
How to mitigate CVE-2020-5256
Install update from vendor's website.