The is-my-json-valid package before 2.12.4 for Node.js has an incorrect exports['utc-millisec'] regular expression, which allows remote attackers to cause a denial of service (blocked event loop) via a crafted string.
https://github.com/advisories/GHSA-ccq6-3qx5-vmqx
https://github.com/advisories/GHSA-f522-ffg8-j8r6
https://nodesecurity.io/advisories/76
https://github.com/mafintosh/is-my-json-valid/commit/eca4beb21e61877d76fdf6bea771f72f39544d9b