CVE-2026-42348: open-telemetry opentelemetry-dotnet-contrib

Vulnerability summary

CVE-2026-42348 is a high (CVSS 7.5) vulnerability in open-telemetry opentelemetry-dotnet-contrib. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 34.3% of scored vulnerabilities.

Timeline

1. 12-05-2026
   PublishedVulnerability first disclosed.
2. 13-05-2026
   Last modifiedVulnerability information updated.

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.

• CWE-789Memory Allocation with Excessive Size ValueThe 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.