Vulnerability · Published May 26, 2026 · Assigned by GitHub_M
CVE-2026-44213OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured
Medium 6.5
In plain English
A medium-severity improper certificate validation in opentelemetry-dotnet-contrib from open-telemetry. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 11% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | opentelemetry.exporter.instana | 1.1.0 | GHSA-wfr5-454p-mjc2 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| open-telemetry | opentelemetry-dotnet-contrib | < 1.1.0 |
Weakness: CWE-295 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N