CVE-2024-53863 Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders

Synapse is an open-source Matrix homeserver. In Synapse versions before 1.120.1, enabling the dynamicthumbnails option or processing a specially crafted request could trigger the decoding and thumbnail generation of uncommon image formats, potentially invoking external tools like Ghostscript for...