Vulnerability-Lookup

CVE-2026-44213 (GCVE-0-2026-44213)

Vulnerability from cvelistv5 – Published: 2026-05-26 21:34 – Updated: 2026-05-27 15:51

Title

OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured

Summary

The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0.

Severity

6.5 (Medium)


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

CWE

CWE-295 - Improper Certificate Validation

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/open-telemetry/opentelemetry-d…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
open-telemetry	opentelemetry-dotnet-contrib	Affected: < 1.1.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-44213",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-27T15:50:57.243988Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-05-27T15:51:25.352Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "opentelemetry-dotnet-contrib",
          "vendor": "open-telemetry",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.1.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-295",
              "description": "CWE-295: Improper Certificate Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-26T21:34:27.762Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2"
        }
      ],
      "source": {
        "advisory": "GHSA-wfr5-454p-mjc2",
        "discovery": "UNKNOWN"
      },
      "title": "OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-44213",
    "datePublished": "2026-05-26T21:34:27.762Z",
    "dateReserved": "2026-05-05T15:13:47.572Z",
    "dateUpdated": "2026-05-27T15:51:25.352Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-44213",
      "date": "2026-05-27",
      "epss": "6e-05",
      "percentile": "0.00309"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-44213\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-05-26T22:16:42.443\",\"lastModified\":\"2026-05-27T17:16:36.323\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N\",\"baseScore\":6.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"HIGH\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.2,\"impactScore\":5.2}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-295\"}]}],\"references\":[{\"url\":\"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-44213\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-05-27T15:50:57.243988Z\"}}}], \"references\": [{\"url\": \"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-05-27T15:50:08.669Z\"}}], \"cna\": {\"title\": \"OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured\", \"source\": {\"advisory\": \"GHSA-wfr5-454p-mjc2\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 6.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"HIGH\", \"confidentialityImpact\": \"HIGH\"}}], \"affected\": [{\"vendor\": \"open-telemetry\", \"product\": \"opentelemetry-dotnet-contrib\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 1.1.0\"}]}], \"references\": [{\"url\": \"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2\", \"name\": \"https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2\", \"tags\": [\"x_refsource_CONFIRM\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-295\", \"description\": \"CWE-295: Improper Certificate Validation\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-05-26T21:34:27.762Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-44213\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-05-27T15:51:25.352Z\", \"dateReserved\": \"2026-05-05T15:13:47.572Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-05-26T21:34:27.762Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-44213

Vulnerability from fkie_nvd - Published: 2026-05-26 22:16 - Updated: 2026-05-27 17:16

Severity

6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The OpenTelemetry.Exporter.Instana exports telemetry to Instana backend. Prior to 1.1.0, the OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable. If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker. This vulnerability is fixed in 1.1.0."
    }
  ],
  "id": "CVE-2026-44213",
  "lastModified": "2026-05-27T17:16:36.323",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 1.2,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-26T22:16:42.443",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-WFR5-454P-MJC2

Vulnerability from github – Published: 2026-05-08 20:48 – Updated: 2026-05-08 20:48

Summary

OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured

Details

Summary

The OpenTelemetry.Exporter.Instana NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the INSTANA_ENDPOINT_PROXY environment variable.

If a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker.

Details

The Transport.ConfigureBackendClient() method creates an HttpClient instance that completely disables TLS server certificate validation if the INSTANA_ENDPOINT_PROXY is configured with a valid proxy URL with no ability to re-enable it.

Impact

If the configured proxy is attacker-controlled (or a network attacker MitM the connection), or if it is possible for the process' configuration to be changed to add an attacker-provided value for INSTANA_ENDPOINT_PROXY then all Instana telemetry could be read by an unauthorized party and the service's Instana API key compromised, potentially before being forwarded to Instana presenting no noticeable loss of telemetry data without a valid TLS server certificate being presented to the client that matches the expected hostname or IP address.

Mitigation

The proxy configured by the INSTANA_ENDPOINT_PROXY environment variable must be malicious or be possible to be subject to a MitM attack.

Workarounds

Do not configure the INSTANA_ENDPOINT_PROXY environment variable.

Remediation

#4153 refactors HttpClient creation so that TLS certificate validation is no longer disabled by default when using a proxy.

In environments where this capability is required, for example for local development, the previous behaviour can be restored using the `` option:

builder.AddInstanaExporter((options) =>
{
    options.HttpClientFactory = () =>
    {
        var handler = new HttpClientHandler()
        {
#if NET
            ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator,
#else
            ServerCertificateCustomValidationCallback = static (_, _, _, _) => true,
#endif
        };
        return new HttpClient(handler, disposeHandler: true);
    };
});

Resources

PR #4153

Severity

6.5 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.0.7"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "OpenTelemetry.Exporter.Instana"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44213"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-295"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-08T20:48:02Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThe `OpenTelemetry.Exporter.Instana` NuGet package does not validate HTTPS/TLS certificates are valid when sending telemetry to a configured Instana back-end when a proxy is configured using the `INSTANA_ENDPOINT_PROXY` environment variable.\n\nIf a network attacker can Man-in-the-Middle (MitM) the proxy connection, all OpenTelemetry telemetry data and the Instana API key are exposed to the attacker.\n\n### Details\n\nThe [`Transport.ConfigureBackendClient()`](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/blob/b53b6a74fde21a4cee344e584b51a0fe5bf1f337/src/OpenTelemetry.Exporter.Instana/Implementation/Transport.cs#L132-L158) method creates an `HttpClient` instance that completely disables TLS server certificate validation if the `INSTANA_ENDPOINT_PROXY` is configured with a valid proxy URL with no ability to re-enable it.\n\n### Impact\n\nIf the configured proxy is attacker-controlled (or a network attacker MitM the connection), or if it is possible for the process\u0027 configuration to be changed to add an attacker-provided value for `INSTANA_ENDPOINT_PROXY` then all Instana telemetry could be read by an unauthorized party and the service\u0027s Instana API key compromised, potentially before being forwarded to Instana presenting no noticeable loss of telemetry data without a valid TLS server certificate being presented to the client that matches the expected hostname or IP address.\n\n### Mitigation\n\nThe proxy configured by the `INSTANA_ENDPOINT_PROXY` environment variable must be malicious or be possible to be subject to a MitM attack.\n\n### Workarounds\n\nDo not configure the `INSTANA_ENDPOINT_PROXY` environment variable.\n\n### Remediation\n\n[#4153](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4153) refactors `HttpClient` creation so that TLS certificate validation is no longer disabled by default when using a proxy.\n\nIn environments where this capability is required, for example for local development, the previous behaviour can be restored using the `` option:\n\n```csharp\nbuilder.AddInstanaExporter((options) =\u003e\n{\n    options.HttpClientFactory = () =\u003e\n    {\n        var handler = new HttpClientHandler()\n        {\n#if NET\n            ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator,\n#else\n            ServerCertificateCustomValidationCallback = static (_, _, _, _) =\u003e true,\n#endif\n        };\n        return new HttpClient(handler, disposeHandler: true);\n    };\n});\n```\n\n### Resources\n\n- [PR #4153](https://github.com/open-telemetry/opentelemetry-dotnet-contrib/pull/4153)",
  "id": "GHSA-wfr5-454p-mjc2",
  "modified": "2026-05-08T20:48:02Z",
  "published": "2026-05-08T20:48:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib/security/advisories/GHSA-wfr5-454p-mjc2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/open-telemetry/opentelemetry-dotnet-contrib"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "OpenTelemetry.Exporter.Instana bypasses TLS certificate validation when a proxy is configured"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

CVE-2026-44213 (GCVE-0-2026-44213)

FKIE_CVE-2026-44213

GHSA-WFR5-454P-MJC2

Summary

Details

Impact

Mitigation

Workarounds

Remediation

Resources

Tags

Sightings

Nomenclature