CVE-2026-40891
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).
Does this matter?
Lower severity and a low EPSS score (0.19%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.19% probability · 9th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-789
- Affected
- opentelemetry/opentelemetry
- Source
- security-advisories@github.com
References
- https://github.com/open-telemetry/opentelemetry-dotnet/pull/5980Issue Tracking, Patch
- https://github.com/open-telemetry/opentelemetry-dotnet/pull/7064Issue Tracking, Patch
- https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-mr8r-92fq-pj8pMitigation, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.