Executive brief
Docmost is an open-source collaborative wiki and documentation platform. A security flaw allows users with basic editing permissions to embed malicious scripts within page attachments. If another user clicks on the affected attachment, the attacker's script will run in their browser, potentially allowing the attacker to steal session information or perform actions on the victim's behalf.
Technical details
A stored cross-site scripting (XSS) vulnerability exists in Docmost due to improper neutralization of attachment URL schemes. While standard link nodes in the editor explicitly block 'javascript:' URIs, the attachment extension fails to apply the same sanitization logic. An authenticated attacker with page-editing privileges can submit a crafted JSON payload containing a malicious 'javascript:' URL within an attachment node. When a victim interacts with the attachment link or icon, the script executes within the context of the application's origin. This issue is fixed in version 0.71.0.
Affected products
- Docmost Docmost < 0.71.0
Timeline
- 2026-03-23: other: Vulnerability validated by researcher
- 2026-04-14: disclosed
- 2026-04-14: advisory
- 2026-04-14: patched: Version 0.71.0 released