CVE-2026-54788: datadog-opentelemetry has unbounded W3C tracestate parsing that may lead to DoS

Datadog tracing libraries that implement W3C Trace Context (tracecontext) propagation parse the incoming tracestate header without enforcing a size cap on the Datadog vendor entry (dd=...). The dd= value contains semicolon-separated key:value pairs, and the parser allocates a hash-map entry for each pair. A remote, unauthenticated attacker can send a tracestate header whose dd= member is arbitrarily large (or contains an arbitrarily large number of pairs), forcing unbounded CPU and memory consumption per request and enabling a remote Denial of Service. tracecontext extraction is enabled by default in affected tracers, so any internet-facing service instrumented with an affected version is exposed unless tracecontext has been explicitly removed from the propagation style configuration.