Executive brief
OpenClaw, a tool used for managing communication channels, contains a flaw in how it handles media from Zalo. An unauthorized user can send messages that force the system to download and store files on its disk before checking if the sender is allowed to communicate. This could lead to unnecessary storage consumption or resource exhaustion on the server hosting the application.
Technical details
An incorrect authorization vulnerability (CWE-863) exists in the Zalo channel extension of OpenClaw within 'extensions/zalo/src/monitor.ts'. The application logic processes and stores inbound media files before performing DM/pairing authorization checks. A remote, unauthenticated attacker can exploit this by sending specially crafted messages via Zalo, forcing the server to perform network fetches and disk I/O operations. While the messages themselves are eventually rejected, the media is already written to the local store, potentially leading to disk exhaustion. This issue is resolved in version 2026.3.28.
Affected products
- OpenClaw OpenClaw < 2026.3.28
Timeline
- 2026-03-29: advisory: Vendor advisory published on GitHub
- 2026-03-31: disclosed: CVE published to NVD