CVE-2026-81870

### Summary OpenTelemetry Go versions 1.5.0 through 1.44.0 can include trace exporter endpoint configuration in an internal diagnostic log emitted when an SDK `TracerProvider` is created. The default OpenTelemetry logger does not emit this event. Exposure requires an application to install a logger that enables OpenTelemetry's internal Info-level diagnostics and for someone other than the intended audience to have access to those logs. The logged configuration can disclose the address of the trace collector and whether the OTLP/HTTP connection is configured as insecure. The Zipkin exporter logs its complete collector URL, so credentials in URL userinfo or tokens in the query string are also disclosed if an application embeds them there. OTLP authentication headers, TLS key material, and exported span data are not included in this log. Exporter `MarshalLog` implementations that caused this configuration to be included in internal logs were introduced by [`a1fff3c`](https://github.com/open-telemetry/opentelemetry-go/commit/a1fff3c2588c783d1f3f6fd2315aa2660fc6d330). ### Details When `sdk/trace.NewTracerProvider` constructs a provider, it records a `TracerProvider created` internal Info event containing the provider configuration. In affected versions, the configuration's `MarshalLog` methods recursively include: 1. the provider's span processors; 2. each processor's span exporter; and 3. for the OTLP trace exporter, its client configuration. This causes the following values to be present in the event: - OTLP trace gRPC: the configured endpoint; - OTLP trace HTTP: the configured endpoint and the `Insecure` flag; and - Zipkin: the complete collector URL. OpenTelemetry Go does not emit this event with its default logger, which only emits errors. An application must explicitly configure a sufficiently verbose logger with `otel.SetLogger`. The required `logr` verbosity is version-dependent: - versions 1.5.0 through 1.14.x use `V(1)` for this Info event; and - vers