GStreamer before 1.18.4 might access already-freed memory in error code paths when demuxing certain malformed Matroska files (SA-2021-0002).
GStreamer before 1.18.4 might cause heap corruption when parsing certain malformed Matroska files (SA-2021-0003).
GStreamer before 1.18.4 might do an out-of-bounds read when handling certain RealMedia files or streams (SA-2021-0004).
GStreamer before 1.18.4 might cause stack corruptions with streams that have more than 64 audio channels (SA-2021-0005).
It might be possible for a malicious third party to trigger a crash in the application, but possibly also an arbitrary code execution with the privileges of the target user.