Heap-based buffer overflow in the yamlparserscanuriescapes function in LibYAML before 0.1.6 allows context-dependent attackers to execute arbitrary code via a long sequence of percent-encoded characters in a URI in a YAML file.

A heap-based buffer overflow flaw was found in the way libyaml parsed YAML tags. A remote attacker could provide a specially-crafted YAML document that, when parsed by an application using libyaml, would cause the application to crash or, potentially, execute arbitrary code with the privileges of the user running the application.

Acknowledgements:

This issue was discovered by Florian Weimer of the Red Hat Product Security Team.