# CVE-2026-42348: OpAMP client reads unbounded HTTP response bodies

> An attacker can cause memory exhaustion in applications using the OpAMP client by sending unbounded HTTP responses, leading to denial of service.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 May 2026
- **Updated:** 13 May 2026
- **Also known as:** GHSA-w2jh-77fq-7gp8

## What is CVE-2026-42348?

CVE-2026-42348 is a medium-severity denial of service vulnerability in open-telemetry opentelemetry-dotnet-contrib, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OpenTelemetry.OpAmp.Client is the OpAMP client for OpenTelemetry .NET. Prior to 0.2.0-alpha.1, 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. This vulnerability is fixed in 0.2.0-alpha.1.

Weakness: CWE-789 (Memory Allocation with Excessive Size Value)

## Which versions are affected by CVE-2026-42348?

2 open source packages ship an affected version, including OpenTelemetry.OpAmp.Client. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `OpenTelemetry.OpAmp.Client` | NuGet | All versions | 0.2.0-alpha.1 |
| `OpenTelemetry.OpAmp.Client` | NuGet | All versions | 0.2.0-alpha.1 |

Products: Opentelemetry Opentelemetry.opamp.client.

## How do I fix CVE-2026-42348?

Upgrade OpenTelemetry.OpAmp.Client to 0.2.0-alpha.1 or later.

## Is CVE-2026-42348 being exploited?

There is no known exploitation of CVE-2026-42348 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42348 and fix it if it is affected.

What it is: CVE-2026-42348 is a medium-severity denial of service vulnerability in open-telemetry opentelemetry-dotnet-contrib, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42348 in the wild and no public exploit code.

Affected packages and fixed versions:
- OpenTelemetry.OpAmp.Client (NuGet): affected all versions; fixed in 0.2.0-alpha.1
- OpenTelemetry.OpAmp.Client (NuGet): affected all versions; fixed in 0.2.0-alpha.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42348/ (Markdown: https://insights.sbomify.com/CVE-2026-42348/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42348
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42348
- OSV: https://osv.dev/vulnerability/CVE-2026-42348

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42348/
Summaries are generated and may contain mistakes; the official description above is the record.