CVE-2026-81872: OpenTelemetry-Go: BatchProcessor can busy-spin when export buffer is full
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. This issue is fixed in version 0.21.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go.opentelemetry.io/otel/sdk/log BatchingProcessorto a version that resolves this vulnerability.Fixed in 0.21.0
Event History
Frequently Asked Questions
Which deployments are exposed to this issue?
Deployments using go.opentelemetry.io/otel/sdk/log BatchingProcessor before version 0.21.0 are affected when their asynchronous export buffer becomes full while the exporter is backpressured. The impact occurs in the embedding Go process, where CPU exhaustion can degrade or deny service.
What conditions are required for exploitation?
An attacker must be able to drive sufficient log emission to keep the processor queue at or above its batch size. The exporter must also be backpressured so that its single-entry asynchronous export buffer cannot accept another export.
Is the default processor construction affected?
Yes. NewBatchingProcessor wraps the exporter with newBufferExporter(exporter, 1), creating a buffer with capacity one. When that buffer is full, a failed nonblocking enqueue can leave the queue unchanged and trigger repeated immediate retries.
How can I determine whether this is occurring?
Look for sustained high CPU consumption in a process using the affected BatchingProcessor during periods of high log volume and exporter backpressure. The processor may repeatedly retry exports without waiting for its ticker while its queue remains at or above batchSize.
What is the available fix?
Upgrade OpenTelemetry-Go to version 0.21.0, which fixes the issue.