CVE-2026-81872 OpenTelemetry-Go: BatchProcessor can busy-spin when export buffer is full
An attacker can cause a denial of service by filling the log export buffer, triggering a CPU busy-spin in the OpenTelemetry-Go BatchProcessor.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-81872?
CVE-2026-81872 is a medium-severity denial of service vulnerability in open-telemetry opentelemetry-go, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-81872?
3 open source packages ship an affected version, including go.opentelemetry.io/otel/sdk/log.
| Package | Affected | Fixed in |
|---|---|---|
go.opentelemetry.io/otel/sdk/log Go | All versions | 0.21.0 |
go.opentelemetry.io/otel/sdk/log Go | All versions | 0.21.0 |
go.opentelemetry.io/otel/sdk/log Go | All versions | 0.21.0 |
How do I fix CVE-2026-81872?
Upgrade go.opentelemetry.io/otel/sdk/log to 0.21.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-81872 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-81872 exists.
Sources
Also known as AZL-103058, AZL-103113, CLEANSTART-2026-GU78315, CLEANSTART-2026-PZ05319, CLEANSTART-2026-RX61384, CLEANSTART-2026-XR03943 and 113 more.