CVE-2026-128086

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.0.0-RC1 until version 1.47.0, baggage.Parse and propagation.Baggage.Extract eagerly materialize every W3C baggage property through parseMember, grow property slices, serialize members, and copy properties into internal/baggage.Item. A valid densely populated baggage header can therefore cause allocation traffic and retained memory disproportionate to its bounded input size. Remote impact requires baggage extraction to be enabled, attacker-controlled input to reach it, and extraction to run before authentication or on a public route; the evidence establishes increased allocation and garbage-collection pressure but not reliable process termination. This issue is fixed in version 1.47.0.