WeRSS Remote Code Execution Vulnerability

The WeRSS (we-mp-rss) application through version 1.5.3 contains a remote code execution vulnerability.

Unauthenticated attackers can execute code by supplying a crafted template parameter to the public GET /rss/{feed_id} endpoint. The exploit requires a non-built-in ext value and a {{=expression}} template whose object-subclass traversal bypasses the eval denylist.

• Affected versions: through 1.5.3
• Preconditions: unauthenticated network access to the /rss/{feed_id} endpoint
• Impact: attackers can run OS commands as the service account