Vulnerability in Open-Telemetry Opentelemetry-Dotnet-Contrib

CVE-2026-44213

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.

Vulnerability class: Improper Certificate Validation

EPSS: 0.002 (10.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-44213?
CVE-2026-44213 is a medium-severity vulnerability in Open-Telemetry Opentelemetry-Dotnet-Contrib, classified under Improper Certificate Validation. CVSS score: 6.5/10. Published 2026-05-26.
How severe is CVE-2026-44213?
Medium severity. CVSS v3 base score is 6.5 out of 10.