ghsa-q834-8qmm-v933

{
  "affected": [
    {
      "database_specific": {
        "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-q834-8qmm-v933/GHSA-q834-8qmm-v933.json"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "OpenTelemetry.Exporter.OpenTelemetryProtocol",
        "purl": "pkg:nuget/OpenTelemetry.Exporter.OpenTelemetryProtocol"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.13.1"
            },
            {
              "fixed": "1.15.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.13.1",
        "1.14.0",
        "1.15.0",
        "1.15.1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40182"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-23T21:26:10Z",
    "nvd_published_at": "2026-04-23T18:16:28Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nWhen 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.\n\nThis 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.\n\n### Details\n\nhttps://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](https://github.com/open-telemetry/opentelemetry-dotnet/blob/640cf63628567b76b348b26988920dbc0b5c1662/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/OtlpGrpcExportClient.cs#L123-L134) and [HTTP/protobuf](https://github.com/open-telemetry/opentelemetry-dotnet/blob/640cf63628567b76b348b26988920dbc0b5c1662/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/OtlpHttpExportClient.cs#L36-L41).\n\nAn unintended consequence of this change is that the response body is [fully read into memory when received with no upper-bound](https://github.com/open-telemetry/opentelemetry-dotnet/blob/640cf63628567b76b348b26988920dbc0b5c1662/src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/ExportClient/OtlpExportClient.cs#L68-L89).\n\nThis vulnerability was surfaced during the investigation of GHSA-w8rr-5gcm-pp58.\n\n### Impact\n\nIf an application using the OTLP exporter is configured to use a back-end/collector endpoint that is attacker-controlled (or a network attacker can MitM the connection) and an extremely large body is returned by the response the application could have its memory exhausted and create a denial-of-service condition.\n\n### Mitigation\n\nThe application's configured back-end/collector endpoint needs to behave maliciously. If the collector/back-end is a well-behaved implementation response bodies should not be excessively large if a request error occurs.\n\n### Workarounds\n\nNone known.\n\n### Remediation\n\n[#7017](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7017) updates the OTLP exporter for both gRPC and HTTP to:\n\n- Limit the number of bytes read from the response body in an error condition to 4MiB (see https://github.com/open-telemetry/opentelemetry-proto/pull/781);\n- Only attempt to read the response body if OpenTelemetry error logging is enabled.",
  "id": "GHSA-q834-8qmm-v933",
  "modified": "2026-09-10T03:51:02.815079557Z",
  "published": "2026-04-23T21:26:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet/security/advisories/GHSA-q834-8qmm-v933"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40182"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet/pull/6564"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet/pull/7017"
    },
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-proto/pull/781"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "OpenTelemetry dotnet: OTLP exporter reads unbounded HTTP response bodies"
}