The yaml_parser_scan_tag_uri function in scanner.c in LibYAML before 0.1.5 performs an incorrect cast, which allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via crafted tags in a YAML document, which triggers a heap-based buffer overflow.
Improper Restriction of Operations within the Bounds of a Memory Buffer The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.