Is CVE-2026-40891 actively exploited?

CVE-2026-40891 has no public evidence of in-the-wild exploitation as of 2026-04-29.

What is the CVSS score for CVE-2026-40891?

CVE-2026-40891 has a CVSS score of 5.3 (MEDIUM severity). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.

How do I patch CVE-2026-40891?

Patch guidance is available from opentelemetry security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-40891.

Which products are affected by CVE-2026-40891?

1 product: opentelemetry opentelemetry.

CVE-2026-40891 - remediation guidance & executive summary

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 Metrics

Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector: adjacent network
Complexity: high
Privileges: none
User Action: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Weaknesses: CWE-789

Metadata

Primary Vendor: OPENTELEMETRY
Published: 4/23/2026
Last Modified: 4/29/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

opentelemetry : opentelemetry

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-40891. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-40891

View on NIST NVD

CVE-2026-40891 vulnerability