Vulnerability details

## Overview A vulnerability affects the baggage propagation implementation in `opentelemetry-api` and `opentelemetry-extension-trace-propagators`. Parsing oversized baggage causes unbounded memory allocation and CPU consumption. Because baggage is automatically re-injected into every outgoing request, the effect can fan out to downstream services that never received the original malicious request. ## Technical Details - `W3CBaggagePropagator` did not enforce any limit on the total size or entry count of the `baggage` header. The parser iterated character-by-character through the entire value regardless of length. - `JaegerPropagator` and `OtTracePropagator` had the same gap in their respective baggage extraction paths. - The W3C Baggage specification recommends a maximum of 8,192 bytes and 180 entries; none of these limits were enforced. ## Impact The practical availability impact for most deployments is limited. Every major Java HTTP server enforces its own header size limit (Tomcat, Jetty, Netty, Vert.x, and gRPC-Java all default to 8 KiB), constraining what an external attacker can deliver before the application is reached. The risk is higher when transport-layer limits are absent — e.g., a compromised internal service communicating over a non-HTTP or custom transport. ## Remediation Update to version 1.62.0 or later ([#8380](https://github.com/open-telemetry/opentelemetry-java/pull/8380)). The fix enforces limits consistent with the W3C Baggage specification at the propagator level: - Maximum total baggage size: 8,192 bytes across all `baggage` header values - Maximum number of entries: 64 Headers that would exceed either limit are dropped at the point the limit is reached; already-extracted valid entries are retained. ## Workarounds Ensure HTTP header size limits are configured at the server or gateway level. Most Java HTTP servers enforce an 8 KiB header limit by default, which mitigates external attack vectors independently of this fix. ## References - [W3C Baggage Specification §Limits](https://www.w3.org/TR/baggage/#limits)