What’s Vulnerable › Vulnerabilities

CVE-2026-40891: OpenTelemetry dotnet: Unbounded `grpc-status-details-bin` parsing in OTLP/gRPC retry handling

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-23 · updated 2026-10-26
• Weakness: CWE-789

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 products

• open-telemetry opentelemetry-go: from 1.13.1 before 1.15.3 — fixed in 1.15.3

How to fix

Upgrade to a fixed version: open-telemetry opentelemetry-go 1.15.3. Check the vendor advisory for mitigations.

References

• https://github.com/open-telemetry/opentelemetry-dotnet/pull/5980
• https://github.com/open-telemetry/opentelemetry-dotnet/pull/7064
• https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-mr8r-92fq-pj8p

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