CVE-2026-41173 Unbounded HTTP response body read in OpenTelemetry.Sampler.AWS
An attacker controlling the sampling endpoint can cause memory exhaustion and process termination by returning large HTTP responses.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-41173?
CVE-2026-41173 is a medium-severity denial of service vulnerability in open-telemetry opentelemetry-dotnet-contrib, published on 23 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The AWS X-Ray Remote Sampler package provides a sampler which can get sampling configurations from AWS X-Ray. Prior to 0.1.0-alpha.8, OpenTelemetry.Sampler.AWS reads unbounded HTTP response bodies from a configured AWS X-Ray remote sampling endpoint into memory. AWSXRaySamplerClient.DoRequestAsync called HttpClient.SendAsync followed by ReadAsStringAsync(), which materializes the entire HTTP response body into a single in-memory string with no size limit. The sampling endpoint is configurable via AWSXRayRemoteSamplerBuilder.SetEndpoint (default: http://localhost:2000). An attacker who controls the configured endpoint, or who can intercept traffic to it (MitM), can return an arbitrarily large response body. This causes unbounded heap allocation in the consuming process, leading to high transient memory pressure, garbage-collection stalls, or an OutOfMemoryException that terminates the process. This vulnerability is fixed in 0.1.0-alpha.8.
Weakness: CWE-770
Which versions are affected by CVE-2026-41173?
4 open source packages ship an affected version, including OpenTelemetry.Resources.AWS and OpenTelemetry.Sampler.AWS.
| Package | Affected | Fixed in |
|---|---|---|
OpenTelemetry.Resources.AWS NuGet | All versions | 1.15.1 |
OpenTelemetry.Resources.AWS NuGet | All versions | 1.15.1 |
OpenTelemetry.Sampler.AWS NuGet | All versions | 0.1.0-alpha.8 |
OpenTelemetry.Sampler.AWS NuGet | All versions | 0.1.0-alpha.8 |
How do I fix CVE-2026-41173?
Upgrade OpenTelemetry.Resources.AWS to 1.15.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-41173 being exploited?
There is no known exploitation of CVE-2026-41173 in the wild and no public exploit code.
Sources
Also known as GHSA-28xm-prxc-5866.