Vulnerability in Open-Telemetry Opentelemetry-Dotnet
CVE-2026-40891
OpenTelemetry dotnet is a dotnet telemetry framework. From 1.13.1 to before 1.15.2, When exporting telemetry over gRPC using the OpenTelemetry Protocol (OTLP), the exporter may parse a server-provided grpc-status-details-bin trailer during retry handling. Prior to the fix, a malformed trailer could encode an extremely large length-delimited protobuf field which was used directly for allocation, allowing excessive memory allocation and potential denial of service (DoS). This vulnerability is fixed in 1.15.2.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (19.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 20th percentile — 19.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- Open-Telemetry Opentelemetry-Dotnet — versions >= 1.13.1, < 1.15.3
- Open-Telemetry Opentelemetry.exporter.opentelemetryprotocol — versions >= 1.13.1, < 1.15.3
- Opentelemetry
Weakness classification (CWE)
References
- github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-mr8r-92… (Mitigation, Vendor Advisory)
- github.com/open-telemetry/opentelemetry-dotnet/pull/5980 (Patch, Issue Tracking)
- github.com/open-telemetry/opentelemetry-dotnet/pull/7064 (Patch, Issue Tracking)
Frequently asked questions
- What is CVE-2026-40891?
- CVE-2026-40891 is a medium-severity vulnerability in Open-Telemetry Opentelemetry-Dotnet, classified under CWE-789. CVSS score: 5.3/10. Published 2026-04-23.
- How severe is CVE-2026-40891?
- Medium severity. CVSS v3 base score is 5.3 out of 10.