YAML versions before 1.27001 for Perl allow a loaded perl/glob document to replace any package variable, which can lead to arbitrary code execution.

A perl/glob document names a package and a symbol, and supplies the value assigned to it. Nothing restricts the name, so the target can be @INC or YAML's own load options.

A perl/glob document that sets $YAML::LoadCode or $YAML::UseCode turns on code loading, which is off by default, for every later Load() in the process. A perl/code document is then passed to a string eval, so an attacker who supplies two documents to separate Load() calls in one process can execute arbitrary Perl code.

YAML::Syck versions before 1.36 for Perl has missing Null-Terminators which causes Out-of-Bounds Read and potential Information Disclosure

Using snakeYAML to parse untrusted YAML files may be vulnerable to Denial of Service attacks (DOS). If the parser is running on user supplied input, an attacker may supply content that causes the parser to crash by stackoverflow.

https://bitbucket.org/snakeyaml/snakeyaml/issues/530/stackoverflow-oss-fuzz-47039 https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=47039

YAML-LibYAML prior to 0.903.0 for Perl uses 2-args open, allowing existing files to be modified

YAML-LibYAML prior to 0.903.0 for Perl uses 2-args open, allowing existing files to be modified