CVE-2025-27513: OpenTelemetry .NET has a Denial of Service (DoS) Vulnerability in API Package
Impact What kind of vulnerability is it? Who is impacted?
A vulnerability in OpenTelemetry.Api package 1.10.0 to 1.11.1 could cause a Denial of Service (DoS) when a tracestate and traceparent header is received.
Even if an application does not explicitly use trace context propagation, receiving these headers can still trigger high CPU usage. This issue impacts any application accessible over the web or backend services that process HTTP requests containing a tracestate header. Application may experience excessive resource consumption, leading to increased latency, degraded performance, or downtime.
Patches Has the problem been patched? What versions should users upgrade to?
This issue has been <strong data-start="1143" data-end="1184">resolved in OpenTelemetry.Api 1.11.2</strong> by <strong data-start="1188" data-end="1212">reverting the change</strong> that introduced the problematic behavior in versions <strong data-start="1266" data-end="1286">1.10.0 to 1.11.1</strong>.</li><li data-start="1290" data-end="1409">The fix ensures that <strong data-start="1313" data-end="1380">valid tracing headers no longer cause excessive CPU consumption</strong> when received in requests.</li></ul><h4 data-start="1411" data-end="1434"><strong data-start="1416" data-end="1434">Fixed Version:</strong></h4> OpenTelemetry .NET Version | Status -- | -- <= 1.9.x | ✅ Not affected 1.10.0 - 1.11.1 | ❌ Vulnerable 1.11.2 (Fixed) | ✅ Safe to use
Upgrade Command:
dotnet add package OpenTelemetry --version 1.11.2
Delisting of Affected Packages To prevent accidental usage, we have delisted the affected versions (1.10.0 to 1.11.1) from NuGet. Users should avoid these versions and upgrade to 1.11.2 immediately.
Workarounds Is there a way for users to fix or remediate the vulnerability without upgrading?
References Are there any links users can visit to find out more?
Other sources
OpenTelemetry dotnet is a dotnet telemetry framework. A vulnerability in OpenTelemetry.Api package 1.10.0 to 1.11.1 could cause a Denial of Service (DoS) when a tracestate and traceparent header is received. Even if an application does not explicitly use trace context propagation, receiving these headers can still trigger high CPU usage. This issue impacts any application accessible over the web or backend services that process HTTP requests containing a tracestate header. Application may experience excessive resource consumption, leading to increased latency, degraded performance, or downtime. This vulnerability is fixed in 1.11.2.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nuget/OpenTelemetry.Apito a version that resolves this vulnerability.Fixed in 1.11.2 - Upgrade
Upgrade
OpenTelemetry.Apito a version that resolves this vulnerability.Fixed in 1.11.2 - Compensating control
For any exposed application/backend service, mitigate the DoS by ensuring HTTP requests containing the tracestate header are not accepted from untrusted sources (e.g., block/limit web traffic that includes tracestate/traceparent headers until upgrading to OpenTelemetry.Api 1.11.2).
Event History
Frequently Asked Questions
What is the severity of CVE-2025-27513?
The severity of CVE-2025-27513 is classified as high due to its potential to cause Denial of Service (DoS).
How do I fix CVE-2025-27513?
To fix CVE-2025-27513, upgrade the OpenTelemetry.Api package to version 1.11.2 or later.
What versions of the OpenTelemetry.Api package are affected by CVE-2025-27513?
CVE-2025-27513 affects OpenTelemetry.Api package versions 1.10.0 to 1.11.1.
What type of vulnerability is CVE-2025-27513?
CVE-2025-27513 is a Denial of Service (DoS) vulnerability caused by unsafe handling of tracestate and traceparent headers.
Can applications not using trace context propagation still be affected by CVE-2025-27513?
Yes, applications that do not explicitly use trace context propagation can still be affected by CVE-2025-27513.