Vulnerability in Open-Telemetry Opentelemetry-Dotnet-Contrib
CVE-2026-42348
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (34.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 34.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Open-Telemetry Opentelemetry-Dotnet-Contrib — versions < 0.2.0-alpha.1
- Opentelemetry Opentelemetry.opamp.client
Weakness classification (CWE)
References
- github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4116 (Issue Tracking)
- github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA… (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-42348?
- CVE-2026-42348 is a medium-severity vulnerability in Open-Telemetry Opentelemetry-Dotnet-Contrib, classified under CWE-789. CVSS score: 5.9/10. Published 2026-05-12.
- How severe is CVE-2026-42348?
- Medium severity. CVSS v3 base score is 5.9 out of 10.