CVE-2026-40182 is a medium-severity (CVSS 5.3) vulnerability in OpenTelemetry.Exporter.OpenTelemetryProtocol. O3 Security confirms whether CVE-2026-40182 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
OpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies
Real-World Exposure
OpenTelemetry.Exporter.OpenTelemetryProtocolReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
OpenTelemetry dotnet is a dotnet telemetry framework. From 1.13.1 to before 1.15.2, When exporting telemetry to a back-end/collector over gRPC or HTTP using OpenTelemetry Protocol format (OTLP), if the request results in a unsuccessful request (i.e. HTTP 4xx or 5xx), the response is read into memory with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured back-end/collector endpoint is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned by the response. This vulnerability is fixed in 1.15.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | OpenTelemetry.Exporter.OpenTelemetryProtocol | ≥ 1.13.1&&< 1.15.2 | 1.15.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for OpenTelemetry.Exporter.OpenTelemetryProtocol. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update OpenTelemetry.Exporter.OpenTelemetryProtocol to 1.15.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40182 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-40182 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-40182. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-40182 in your dependencies?
O3 detects CVE-2026-40182 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.