GHSA-gfg9-5357-hv4c: OpenClaw: Webchat audio embedding could read local files without local-root containment

OpenClaw deployments before 2026.4.15 could embed host-local audio files into webchat responses without applying the local media root containment check used by other media-serving paths.

If an attacker could influence an agent or tool-produced ReplyPayload.mediaUrl, the webchat audio embedding helper could resolve an absolute local path or file: URL, read an audio-like file under the size cap, and base64-encode it into the webchat media response. This crossed the model/tool-output boundary into a host file read. Prompt injection or malicious tool output is a delivery mechanism; the security boundary failure is the missing local-root containment check.

The impact is narrow: the file had to be readable by the gateway process, have an audio-like extension, and fit within the webchat audio size cap. The issue exposed contents into the webchat assistant/media transcript path; it was not a general remote filesystem API.