FFmpeg MPEG-DASH vulnerabilities (CVE)

Heap-buffer-overflow write in FFmpeg MDASH resolve_content_path

When calculating the content path in handling of MPEG-DASH manifests, there's an out-of-bounds NUL-byte write one byte past the end of the buffer.When we call xmlNodeGetContent below [0], it returns a buffer precisely allocated to match the string length, usi…