Vulnerabilities in pkg:nuget/OpenTelemetry.OpAmp.Client

PACKAGE
Advisory Identifier: GHSA-w2jh-77fq-7gp8
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Advisory Summary

CVE-2026-42348 is a MODERATE (CVSS 5.9) opamp client reads unbounded http vulnerability (CWE-789: Memory Allocation with Excessive Size Value) affecting OpenTelemetry.OpAmp.Client libraries in the NuGet ecosystem. The issue involves opamp client reads unbounded http response bodies. Remediation is available by upgrading affected packages to version 0.2.0-alpha.1.

1 Known Advisory Record(s)
Package Vulnerability Intelligence

pkg:nuget/OpenTelemetry.OpAmp.Client

1 Known Advisory Record(s)

Vulnerability advisories affecting package pkg:nuget/OpenTelemetry.OpAmp.Client. Select an advisory below to view technical details or fixes.

Advisory ID CVE / NVD Severity Summary
GHSA-w2jh-77fq-7gp8 CVE-2026-42348 MODERATE OpAMP client reads unbounded HTTP response bodies

CVE-2026-42348 at a Glance

CVE Identifier CVE-2026-42348
GHSA Identifier GHSA-w2jh-77fq-7gp8
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-789: Memory Allocation with Excessive Size Value
Affected Product OpenTelemetry.OpAmp.Client
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-42348

To remediate this vulnerability, upgrade all affected OpenTelemetry.OpAmp.Client dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

OpenTelemetry.OpAmp.Client fixed: 0.2.0-alpha.1 
Upgrade OpenTelemetry.OpAmp.Client to 0.2.0-alpha.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for OpenTelemetry.OpAmp.Client

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-42348, inspect your project dependencies for OpenTelemetry.OpAmp.Client:

inspect dependencies for OpenTelemetry.OpAmp.Client

Analyze the terminal output to locate any version of OpenTelemetry.OpAmp.Client in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.2.0-alpha.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-789: Memory Allocation with Excessive Size Value, where the product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated. In OpenTelemetry.OpAmp.Client, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary When receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. ### Details [#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926) introduced the initial HTTP transport components which uses `ReadAsByteArrayAsync` to copy the `HttpResponseMessage.Content` into a byte array. This code path allows an unbounded read of the entire HTTP response message. ### Impact If an application using the OpAMP client is configured to use an OpAMP server that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response, the application could have its memory exhausted and create a denial-of-service condition. ### Mitigation The application's configured OpAMP server needs to behave maliciously. If the OpAMP server is a well-behaved implementation, response bodies should not be excessively large. ### Workarounds None known. ### Remediation [#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116) updates the OpAMP client HTTP transport to limit the maximum size of responses to 128KB. ### Resources - [#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926) - [#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116) - [CWE-789](https://cwe.mitre.org/data/definitions/789.html)

CVE-2026-42348 Affected OpenTelemetry.OpAmp.Client Versions

1 component(s)
Fixed Versions:
0.2.0-alpha.1
Product / Package Ecosystem Affected Versions Fixed Version
OpenTelemetry.OpAmp.Client
nuget/OpenTelemetry.OpAmp.Client
NuGet
< 0.2.0-alpha.1
0.2.0-alpha.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-w2jh-77fq-7gp8
NVD — CVE-2026-42348 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-42348
OpenTelemetry.OpAmp.Client Source Repository REPOSITORY
https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116
Security Fix Commit FIX COMMIT
https://github.com/open-telemetry/opentelemetry-dotnet-contrib/commit/bf1fad4fa298ff451cda0efb0ee9c7a7eb46212a
OpenTelemetry.OpAmp.Client Source Repository REPOSITORY
https://github.com/open-telemetry/opentelemetry-dotnet-contrib

Frequently Asked Questions

What is CVE-2026-42348?
CVE-2026-42348 is a security vulnerability in OpenTelemetry.OpAmp.Client involving OpAMP client reads unbounded HTTP response bodies under CWE-789: Memory Allocation with Excessive Size Value.
Which OpenTelemetry.OpAmp.Client versions are affected?
Affected versions include releases prior to 0.2.0-alpha.1 across affected packages: OpenTelemetry.OpAmp.Client.
What version fixes CVE-2026-42348?
Upgrading to 0.2.0-alpha.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is OpenTelemetry.OpAmp.Client affected?
Yes, OpenTelemetry.OpAmp.Client is affected in releases prior to 0.2.0-alpha.1. Upgrade your dependency to 0.2.0-alpha.1 or later.
What is the CVSS score of CVE-2026-42348?
CVE-2026-42348 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-42348?
CVE-2026-42348 is classified under CWE-789: Memory Allocation with Excessive Size Value (The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.).
How can I check NuGet dependencies for CVE-2026-42348?
Run the dependency tree command: 'inspect dependencies for OpenTelemetry.OpAmp.Client'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-w2jh-77fq-7gp8",
  "modified" : "2026-05-13T16:27:09Z",
  "published" : "2026-05-05T21:57:54Z",
  "aliases" : [ "CVE-2026-42348" ],
  "summary" : "OpAMP client reads unbounded HTTP response bodies",
  "details" : "### Summary\n\nWhen receiving responses from the OpAMP server over HTTP, the OpAMP client allocates an unbounded buffer to read all bytes from the server, with no upper-bound on the number of bytes consumed.\n\nThis could cause memory exhaustion in the consuming application if the configured OpAMP server is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response. \n\n### Details\n\n[#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926) introduced the initial HTTP transport components which uses `ReadAsByteArrayAsync` to copy the `HttpResponseMessage.Content` into a byte array. This code path allows an unbounded read of the entire HTTP response message.\n\n### Impact\n\nIf an application using the OpAMP client is configured to use an OpAMP server that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned in the response, the application could have its memory exhausted and create a denial-of-service condition.\n\n### Mitigation\n\nThe application's configured OpAMP server needs to behave maliciously. If the OpAMP server is a well-behaved implementation, response bodies should not be excessively large.\n\n### Workarounds\n\nNone known.\n\n### Remediation\n\n[#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116) updates the OpAMP client HTTP transport to limit the maximum size of responses to 128KB.\n\n### Resources\n\n- [#2926](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/2926)\n- [#4116](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116)\n- [CWE-789](https://cwe.mitre.org/data/definitions/789.html)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "OpenTelemetry.OpAmp.Client"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.2.0-alpha.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-w2jh-77fq-7gp8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-42348"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/commit/bf1fad4fa298ff451cda0efb0ee9c7a7eb46212a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/open-telemetry/opentelemetry-dotnet-contrib"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-789" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-05T21:57:54Z",
    "nvd_published_at" : "2026-05-12T18:17:24Z"
  }
}