Please report security issues privately through GitHub's private vulnerability reporting rather than in a public issue. Expect a first response within seven days.

• Anything that lets an attacker recover AVATAR_SECRET or the original userId from generated images or from the HTTP endpoint.
• Crashes, hangs or unbounded memory use triggered by untrusted userId, size or style input.
• Output that escapes the SVG or PNG structure, for example injected markup.

• Visual collisions between avatars. Any finite identicon has them; see the uniqueness note in the README for the recommended mitigation.
• Running the generator without a secret, or with a secret that is shipped to the client. The README explains why the secret has to stay on the backend.
• Denial of service from generating very large images on purpose — cap size at your own edge.

The latest release on main is supported.