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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42348?
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
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 | 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 include Opentelemetry Opentelemetry.opamp.client.
How do I fix CVE-2026-42348?
Upgrade OpenTelemetry.OpAmp.Client to 0.2.0-alpha.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-2026-42348 being exploited?
There is no known exploitation of CVE-2026-42348 in the wild and no public exploit code.
Sources
Also known as GHSA-w2jh-77fq-7gp8.