GHSL-2024-263: Gstreamer NULL-pointer dereference in LRC subtitle parser

GStreamer is a library for constructing graphs of media-handling components. A null pointer dereference vulnerability has been detected in the parse_lrc function within gstsubparse.c. The parse_lrc function calls strchr() to find the character ']' in the string line. The pointer returned by this call is then passed to g_strdup(). However, if the string line does not contain the character ']', strchr() returns NULL, and a call to g_strdup(start + 1) leads to a null pointer dereference. This vulnerability is fixed in 1.24.10.