CVE-2026-48504: opentelemetry_sdk has unbounded memory allocation in W3C Baggage propagation

BaggagePropagator::extract_with_context in opentelemetry_sdk did not enforce the W3C Baggage size limits before parsing an inbound baggage header. A large attacker-controlled header could cause unnecessary CPU work and short-lived heap allocations while parsing entries that would later be discarded by the SDK’s baggage storage limits.

The SDK now applies limits aligned with the W3C Baggage limits:

• 64 list-members
• 8192 bytes total