Datadog dd-trace-py is the Datadog Python APM client. From 1.5.0 until 3.19.9 and 4.15.6, the default query-string obfuscation regular expression can exhibit excessive backtracking while synchronously processing attacker-controlled URL query strings for HTTP span metadata. A remote attacker can cause prolonged CPU consumption, request latency, and service unavailability in affected HTTP tracing integrations that include query strings in URL span tags. The vulnerable processing is enabled by default for those integrations. This issue is fixed in versions 3.19.9 and 4.15.6.