toml-node is a TOML parser for Node.js and the browser. Prior to 5.0.1, the toml.parse() compilers addTableArray() function in lib/compiler.js rescans the complete assignedPaths and valueAssignments bookkeeping sets for every array-of-tables header. Distinct [[name]] paths are not pruned, so a document with many such headers causes quadratic synchronous work and can block the Node.js event loop, denying service to other operations in the process. This issue is fixed in version 5.0.1.
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.