SB2020030917 - Arbitrary file upload in BookStack

Description

This security bulletin contains information about 1 security vulnerability.

1) Arbitrary file upload (CVE-ID: CVE-2020-5256)

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.

Remediation

Install update from vendor's website.

References

• https://github.com/BookStackApp/BookStack/releases/tag/v0.25.3
• https://github.com/BookStackApp/BookStack/releases/tag/v0.25.4
• https://github.com/BookStackApp/BookStack/releases/tag/v0.25.5
• https://github.com/BookStackApp/BookStack/security/advisories/GHSA-g9rq-x4fj-f5hx