CVE-2026-81871

OpenTelemetry-Go is the Go implementation of OpenTelemetry. Prior to version 0.21.0, the go.opentelemetry.io/otel/sdk/log BatchingProcessor can enter a tight CPU loop when attacker-driven log emission fills its asynchronous export buffer while the exporter is backpressured. NewBatchingProcessor wraps the exporter with newBufferExporter(exporter, 1), and the poll loop calls queue.TryDequeue and bufferExporter.EnqueueExport before immediately signaling pollTrigger whenever the queue remains at or above batchSize. Because a failed nonblocking EnqueueExport leaves the queue length unchanged, the processor repeatedly retries without waiting for its ticker, exhausting CPU and degrading or denying service in the embedding process.

OpenTelemetry-Go is the Go implementation of OpenTelemetry. From version 1.10.0 until 1.33.0, the sdk/trace/span.go attribute truncation path can fail to enforce AttributeValueLengthLimit for string and string-slice attributes containing the valid Unicode replacement character U+FFFD. safeTruncateValidUTF8 treats the valid replacement rune as invalid UTF-8 and returns the original input, while strings.ToValidUTF8 leaves that valid rune unchanged, so a second safeTruncate attempt can also return the oversized value. An attacker who controls span attribute content can retain values longer than the configured limit, increasing per-span memory use and weakening denial-of-service protection in the instrumented process.

OpenTelemetry-Go versions 1.5.0 through 1.44.0 emit an internal Info-level diagnostic event from sdk/trace.NewTracerProvider whose MarshalLog implementations recursively include span processor, exporter, and client configuration. Applications calling otel.SetLogger to enable internal Info logging can therefore record OTLP gRPC and HTTP collector endpoints, the OTLP HTTP Insecure flag, and complete Zipkin collector URLs.

OpenTelemetry-Go versions 0.11.0 through 1.44.0 have a panic vulnerability in the OpenTracing bridge due to an unsynchronized extraBaggageItems map, causing concurrent access issues and denial of service. Fixed in 1.45.0.

OpenTelemetry-Go prior to version 0.0.17 leaks one file descriptor on each successful `ParseFile` call. Repeated parsing in a long-running process can exhaust the file descriptor limit and cause denial of service.

OpenTelemetry-Go versions 1.41.0 and 1.43.0 removed raw-length rejection, causing `Parse` to process arbitrarily large/invalid baggage headers and log errors, enabling DoS via oversized inputs. Versions 1.42.0 and 1.44.0 fix the issue.

In OpenTelemetry-Go from 1.15.0 to 1.42.0, the fix for CVE-2026-24051 changed the Darwin ioreg command to use an absolute path but left the BSD kenv command using a bare name, allowing the same PATH hijacking attack on BSD and Solaris platforms.

The OpenTelemetry-Go library prior to version 1.43.0 reads the full HTTP response body into an in-memory buffer without a size cap, which can lead to memory exhaustion when the configured collector endpoint is attacker-controlled or when the connection is intercepted.

OpenTelemetry-Go versions 1.36.0 to 1.40.0 process 'baggage' headers in a way that allows an attacker to amplify CPU and memory allocation by sending many header lines, even if each value is within the 8192-byte limit.