Vulnerability · Published Apr 23, 2026 · Assigned by GitHub_M
CVE-2026-40891OpenTelemetry dotnet: Unbounded `grpc-status-details-bin` parsing in OTLP/gRPC retry handling
Medium 5.3
In plain English
A medium-severity security flaw in opentelemetry-dotnet from open-telemetry. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
OpenTelemetry dotnet is a dotnet telemetry framework. From 1.13.1 to before 1.15.2, When exporting telemetry over gRPC using the OpenTelemetry Protocol (OTLP), the exporter may parse a server-provided grpc-status-details-bin trailer during retry handling. Prior to the fix, a malformed trailer could encode an extremely large length-delimited protobuf field which was used directly for allocation, allowing excessive memory allocation and potential denial of service (DoS). This vulnerability is fixed in 1.15.2.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | opentelemetry.exporter.opentelemetryprotocol | 1.15.3 | GHSA-mr8r-92fq-pj8p |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| open-telemetry | opentelemetry-dotnet | >= 1.13.1, < 1.15.3 |
| open-telemetry | OpenTelemetry.Exporter.OpenTelemetryProtocol | >= 1.13.1, < 1.15.3 |
Weakness: CWE-789 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H