CVE-2025-27513 is a high-severity (CVSS 7.5) CWE-770 vulnerability in OpenTelemetry.Api. A fix is available for OpenTelemetry.Api — see the affected versions and patch details below.
OpenTelemetry .NET has a Denial of Service (DoS) Vulnerability in API Package
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-27513.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-27513 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
OpenTelemetry.Api.NETOpenTelemetry.Api.NETOpenTelemetry.Api.NETOpenTelemetry.Api.NETOpenTelemetry.ApiReal-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
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
tracestateheader. - 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?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | OpenTelemetry.Api | ≥ 1.11.0&&< 1.11.2 | 1.11.2dotnet add package OpenTelemetry.Api --version 1.11.2 |
| .NETNuGet | OpenTelemetry.Api | all versions | No fix |
| .NETNuGet | OpenTelemetry.Api | all versions | No fix |
| .NETNuGet | OpenTelemetry.Api | all versions | No fix |
| .NETNuGet | OpenTelemetry.Api | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for OpenTelemetry.Api, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update OpenTelemetry.Api to 1.11.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-27513 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-27513 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-27513. 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-2025-27513 in your dependencies?
O3 Security finds CVE-2025-27513 across NuGet dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.