Regular Expression Denial of Service (REDoS) in UAParser.js

Snyk’s monthly profile describes a REDoS vulnerability in the popular UAParser JavaScript package (CVE-2020-7733) discovered by Yeting Li; a proof-of-concept shows that appending a long sequence of spaces plus an exclamation point to a user-agent triggers catastrophic regex backtracking, potentially causing Node.js servers to hang. The issue was responsibly disclosed, patched within 72 hours, and Snyk reported that roughly 21,000 monitored packages depended on vulnerable versions, enabling widespread notification and remediation.