parse() can be forced into an infinite loop when a value inside an array or inline table is followed by a comment that has no trailing newline (i.e. the comment "ends" the document). The library fails to exit an internal loop when attempting to find the end of the structure, resetting its cursor to the beginning of the string instead. This causes the parser to indefinitely hang, compromising the availability …
An attacker can send a maliciously crafted TOML to cause the parser to crash, because of a stack overflow caused by thousands of consecutive commented lines. The library uses recursion internally while parsing to skip over commented lines, which can be exploited to crash an application that is processing arbitrary TOML documents.
An attacker can send a maliciously crafted TOML to cause the parser to crash because of a stack overflow caused by a deeply nested inline structure. A similar problem occurs when attempting to stringify deeply nested objects. The library does not limit the maximum exploration depth while parsing or producing TOML documents, nor does it offer a way to do so.