Use After Free
GStreamer before 1.18.4 might access already-freed memory in error code paths when demuxing certain malformed Matroska files.
CWE-416 - Use After Free
Use-after-free (UaF) vulnerability occurs when the application is using a pointer to memory that has been freed. Any attempt to read/write to a buffer after it is de-allocated allows memory corruption, sensitive information exposure, and can potentially lead to arbitrary code execution.