OpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-40182: 0.30% estimated exploitation activity in the next 30 days; percentile 23.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary When exporting telemetry to a back-end/collector over gRPC or HTTP using OpenTelemetry Protocol format (OTLP), if the request results in a unsuccessful request (i.e. HTTP 4xx or 5xx), the response is read into memory with no upper-bound on the number of bytes consumed. This could cause memory exhaustion in the consuming application if the configured back-end/collector endpoint is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned by the response. Details https://github.com/open-telemetry/opentelemetry-dotnet/pull/6564 introduced a change to read the response body when a non-200 HTTP status code is received when exporting telemetry to aid debugging by operators so that the error response is included in the logs emitted by the exporter for both gRPC and HTTP/protobuf. An unintended consequence of this change is that the response body is fully read into memory when received with no upper-bound. This vulnerability was…

Published by the source

23 Apr 2026, 21:26 UTC

Last modified by the source

23 Apr 2026, 21:26 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-q834-8qmm-v933

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# Patch Next advisory brief: CVE-2026-40182

Advisory: OpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies
IDs: CVE-2026-40182, GHSA-q834-8qmm-v933
Record: https://patchnext.com/advisories/cve-2026-40182 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: opentelemetry.exporter.opentelemetryprotocol 1.15.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet opentelemetry.exporter.opentelemetryprotocol: affected >= 1.13.1, < 1.15.2; fixed in 1.15.2

## Suggested inspection (read-only)
- NuGet opentelemetry.exporter.opentelemetryprotocol: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on opentelemetry.exporter.opentelemetryprotocol.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-q834-8qmm-v933 (GitHub-reviewed advisory GHSA-q834-8qmm-v933 lists affected ranges: NuGet opentelemetry.exporter.opentelemetryprotocol >=1.13.1 <1.15.2)

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