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. http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2013-6393