YamlDotNet version 4.3.2 and earlier contains a Insecure Direct Object Reference vulnerability in The default behavior of Deserializer.Deserialize() will deserialize user-controlled types in the line "currentType = Type.GetType(nodeEvent.Tag.Substring(1), throwOnError: false);" and blindly instantiates them. that can result in Code execution in the context of the running process. This attack appear to be exploitable via Victim must parse a specially-crafted YAML file. This vulnerability appears to have been fixed in 5.0.0.

High severity vulnerability that affects YamlDotNet and YamlDotNet.Signed