The Datadog PHP Tracer provides application performance monitoring and distributed tracing for PHP. Prior to 1.19.2, ddtracedeserializebaggage in ext/distributedtracingheaders.c parses incoming W3C baggage HTTP headers without enforcing DDTRACEBAGGAGEMAXITEMS or DDTRACEBAGGAGEMAXBYTES. A remote unauthenticated client can send an arbitrarily large number of comma-separated key-value pairs or a single oversized value, causing the tracer to allocate hash-map entries and consume unbounded CPU and memory on each request. Baggage extraction is enabled by default in most affected deployments unless baggage is removed from DDTRACEPROPAGATIONSTYLE or DDTRACEPROPAGATIONSTYLEEXTRACT. This issue is fixed in version 1.19.2.