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Unbounded HTTP response body read in OpenTelemetry.Sampler.AWS

Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

CVE-2026-41173

Exact risk observation. Current source statements above are a separate evidence layer. Latest risk evidence.

No KEV entry is attached to this observation; this is not evidence that exploitation is absent.

FIRST EPSS: 0.38 % · percentile 30.60 % · scored 24 Oct 2026. Retained older prediction.

Observed 25 Oct 2026 02:24:38 UTC · Complete immutable risk JSON

cve-program · CVE-2026-41173

Published

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.

Source published
23 Apr 2026 18:22:31 UTC
Source modified
23 Apr 2026 19:16:04 UTC
Observed here
23 Oct 2026 15:48:27 UTC
Source terms
CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

euvd · EUVD-2026-25271

Published

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.

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Apr 23, 2026, 6:22:31 PM

dateUpdated: Apr 23, 2026, 7:16:04 PM

Source published
Apr 23, 2026, 6:22:31 PM (timezone not stated)
Source modified
Apr 23, 2026, 7:16:04 PM (timezone not stated)
Observed here
28 Oct 2026 05:06:59 UTC
Source terms
ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd · CVE-2026-41173

Published

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.

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Awaiting Analysis

Weakness classifications: CWE-770

Original publisher date fields

published: 2026-04-23T19:17:29.083

lastModified: 2026-10-26T21:10:00.170

Source published
23 Apr 2026 19:17:29 UTC
Source modified
26 Oct 2026 21:10:00 UTC
Observed here
27 Oct 2026 10:10:07 UTC
Source terms
NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

osv · GHSA-28xm-prxc-5866

Published

### Summary `OpenTelemetry.Sampler.AWS` reads unbounded HTTP response bodies from a configured AWS X-Ray remote sampling endpoint into memory. `OpenTelemetry.Resources.AWS` reads unbounded HTTP response bodies from a configured AWS EC2/ECS/EKS remote instance metadata service endpoint into memory. Both of these would allow an attacker-controlled endpoint or be acting as a Man-in-the-Middle (MitM) to cause excessive memory allocation and possible process termination (via Out of Memory (OOM)). ### Details #### OpenTelemetry.Sampler.AWS `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. #### OpenTelemetry.Resources.AWS The [`AWSEC2Detector`](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/blob/171c6b81f88831641b56b470e6f92862e605013d/src/OpenTelemetry.Resources.AWS/AWSEC2Detector.cs), [`AWSECSDetector`](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/blob/171c6b81f88831641b56b470e6f92862e605013d/src/OpenTelemetry.Resources.AWS/AWSECSDetector.cs) and [`AWSEKSDetector`](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/blob/171c6b81f88831641b56b470e6f92862e605013d/src/OpenTelemetry.Resources.AWS/AWSEKSDetector.cs) classes all make HTTP requests to the relevant AWS metadata service (`http://169.254.169.254`, `ECS_CONTAINER_METADATA_URI`/`ECS_CONTAINER_METADATA_URI_V4` or `https://kubernetes.default.svc` respectively) to obtain metadata about the running process and its infrastructure. An attacker who controls the configured endpoint(s), or who can intercept traffic to them (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. ### Impact Denial of Service (DoS). An attacker can destabilize or crash the application by forcing unbounded memory allocation through the X-Ray sampling and/or EC2/ECS/EKS HTTP response paths. ### Mitigating Factors - The default X-Ray sampling endpoint is `http://localhost:2000`, which limits remote exposure in default configurations. - Risk increases materially when operators configure the sampler to point at a remote or untrusted endpoint. ### Patches Fixed in `OpenTelemetry.Sampler.AWS` version `0.1.0-alpha.8` and `OpenTelemetry.Resources.AWS` version `1.15.1`. The fixes (#4100, #4122) introduce changes that introduce limits to `HttpClient` requests so that the response body is streamed rather than buffered entirely in memory. ### Workarounds - Ensure the X-Ray sampling endpoint (`http://localhost:2000` by default) is not accessible to untrusted parties. - Use network-level controls (firewall rules, mTLS, service mesh) to prevent Man-in-the-Middle (MitM) attacks on the sampling endpoint and/or EC2/ECS/EKS connection. - If using a remote endpoint, place it behind a reverse proxy that enforces a response body size limit.

Source published
23 Apr 2026 21:44:31 UTC
Source modified
23 Apr 2026 22:11:25 UTC
Observed here
23 Oct 2026 16:01:25 UTC
Source terms
GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · MODERATE

ChangeIntel

An IT change radar: releases, security, known issues, retirements, documentation changes, and service status from public sources. Every item links to supporting evidence; dates and statuses can change after they are read.

Sources read 30 Oct 04:09 UTC · 272 of 272 readable · 270 fully read · documentation 469/469 current