SnakeYaml's Constructor() class does not restrict types which can be instantiated during deserialization. Deserializing yaml content provided by an attacker can lead to remote code execution. We recommend using SnakeYaml's SafeConsturctor when parsing untrusted content to restrict deserialization. We recommend upgrading to version 2.0 and beyond.

A vulnerability was discovered in the PyYAML library in versions before 5.4, where it is susceptible to arbitrary code execution when it processes untrusted YAML files through the full_load method or with the FullLoader loader. Applications that use the library to process untrusted input may be vulnerable to this flaw. This flaw allows an attacker to execute arbitrary code on the system by abusing the python/object/new constructor. This flaw is due to an incomplete fix for CVE-2020-1747.

An issue was discovered in Esoteric YamlBeans through 1.15. It allows untrusted deserialisation to Java classes by default, where the data and class are controlled by the author of the YAML document being processed.

An issue was discovered in Esoteric YamlBeans through 1.15. A crafted YAML document is able perform am XML Entity Expansion attack against YamlBeans YamlReader. By exploiting the Anchor feature in YAML, it is possible to generate a small YAML document that, when read, is expanded to a large size, causing CPU and memory consumption, such as a Java Out-of-Memory exception.

Uncaught Exception in GitHub repository eemeli/yaml prior to 2.0.0-5.

Parsing malicious or large YAML documents can consume excessive amounts of CPU or memory.

Due to unbounded alias chasing, a maliciously crafted YAML file can cause the system to consume significant system resources. If parsing user input, this may be used as a denial of service vector.

The d8s-yaml package for Python, as distributed on PyPI, included a potential code-execution backdoor inserted by a third party. The backdoor is the democritus-file-system package. The affected version is 0.1.0.

Those 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 stack overflow. This effect may support a denial of service attack.

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 stack-overflow.