CVE-2026-116589: Datadog dd-trace-py: IAST instrumentation can lead to application DOS

Datadog dd-trace-py is the Datadog Python APM client. From 3.13.0 until 4.15.5, the IAST string-processing instrumentation does not properly handle certain internal errors while old-style % string formatting processes attacker-controlled input. An unhandled error can terminate the Python process and interrupt the work it is handling. Exploitation requires IAST to be enabled, which is not the default, and application code to apply the affected formatting operation to attacker-controlled input. This issue is fixed in version 4.15.5.