dd-trace is the Datadog APM client for Node.js. From 2.0.0 until 5.131.1 and 6.20.1, the default DD_TRACE_OBFUSCATION_QUERY_STRING_REGEXP can perform excessive backtracking on attacker-controlled URL query strings. The expression is applied synchronously while recording HTTP URL metadata, allowing a crafted request to consume excessive CPU, stall request processing, and make the instrumented application unavailable. This issue is fixed in versions 5.131.1 and 6.20.1.