# CVE-2026-44213: OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured

> A network attacker can intercept telemetry and API keys via Man-in-the-Middle attacks when a proxy is configured, due to disabled TLS certificate validation.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 May 2026
- **Updated:** 27 May 2026
- **Also known as:** GHSA-wfr5-454p-mjc2

## What is CVE-2026-44213?

CVE-2026-44213 is a medium-severity vulnerability in open-telemetry opentelemetry-dotnet-contrib, published on 26 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### 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.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-44213?

2 open source packages ship an affected version, including OpenTelemetry.Exporter.Instana.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `OpenTelemetry.Exporter.Instana` | NuGet | All versions | 1.1.0 |
| `OpenTelemetry.Exporter.Instana` | NuGet | All versions | 1.1.0 |

## How do I fix CVE-2026-44213?

Upgrade OpenTelemetry.Exporter.Instana to 1.1.0 or later.

## Is CVE-2026-44213 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44213 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-44213 and fix it if it is affected.

What it is: CVE-2026-44213 is a medium-severity vulnerability in open-telemetry opentelemetry-dotnet-contrib, published on 26 May 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44213 exists.

Affected packages and fixed versions:
- OpenTelemetry.Exporter.Instana (NuGet): affected all versions; fixed in 1.1.0
- OpenTelemetry.Exporter.Instana (NuGet): affected all versions; fixed in 1.1.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-44213/ (Markdown: https://insights.sbomify.com/CVE-2026-44213/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-44213
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-44213
- OSV: https://osv.dev/vulnerability/CVE-2026-44213

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-44213/
Summaries are generated and may contain mistakes; the official description above is the record.