CVE-2024-56515 Untrusted file formats can be thumbnailed, invoking potentially further untrusted decoders in Matrix Media Repo

Matrix Media Repo MMR is a highly configurable multi-homeserver media repository for Matrix. If SVG or JPEGXL thumbnailers are enabled they are disabled by default, a user may upload a file which claims to be either of these types and request a thumbnail to invoke a different decoder in...