# CVE-2026-40891

> Vulnerability · severity: **MEDIUM** (CVSS 5.3).

## 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.

## Key facts

- **CVE ID:** CVE-2026-40891
- **Published:** 2026-04-23
- **CVSS severity:** MEDIUM
- **CVSS base score:** 5.3
- **CWE codes:** CWE-789

## Affected products

- `opentelemetry:opentelemetry`

## Primary sources

- NIST NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40891

## Citation

> AI Analytics. CVE-2026-40891. Retrieved 2026-08-09 from https://api.ai-analytics.org/cve/CVE-2026-40891. Derived from NIST NVD. Licensed CC0.

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