Vulnerability-Lookup

CVE-2026-85720 (GCVE-0-2026-85720)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:00 – Updated: 2026-09-17 16:00

Title

AsyncHttpClient: Origin credentials sent to the proxy on the plaintext CONNECT request

Summary

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12.

Severity

5.9 (Medium)


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

CWE

CWE-319 - Cleartext Transmission of Sensitive Information
CWE-522 - Insufficiently Protected Credentials

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/AsyncHttpClient/async-http-cli…	x_refsource_CONFIRM
https://github.com/AsyncHttpClient/async-http-cli…	x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-cli…	x_refsource_MISC
https://github.com/AsyncHttpClient/async-http-cli…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
AsyncHttpClient	async-http-client	Affected: >= 2.0.0, < 2.16.1 Affected: >= 3.0.0, < 3.0.12	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "async-http-client",
          "vendor": "AsyncHttpClient",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.16.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.0.12"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-319",
              "description": "CWE-319: Cleartext Transmission of Sensitive Information",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-522",
              "description": "CWE-522: Insufficiently Protected Credentials",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:00:01.615Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf"
        },
        {
          "name": "https://github.com/AsyncHttpClient/async-http-client/pull/2234",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/AsyncHttpClient/async-http-client/pull/2234"
        },
        {
          "name": "https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6"
        },
        {
          "name": "https://github.com/AsyncHttpClient/async-http-client/commit/d07dbc79f5cf378f63c246f6101d7579ace55acc",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/AsyncHttpClient/async-http-client/commit/d07dbc79f5cf378f63c246f6101d7579ace55acc"
        }
      ],
      "source": {
        "advisory": "GHSA-xr57-gcx8-52hf",
        "discovery": "UNKNOWN"
      },
      "title": "AsyncHttpClient: Origin credentials sent to the proxy on the plaintext CONNECT request"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-85720",
    "datePublished": "2026-09-17T16:00:01.615Z",
    "dateReserved": "2026-09-04T14:45:10.648Z",
    "dateUpdated": "2026-09-17T16:00:01.615Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "async-http-client",
                "vendor": "AsyncHttpClient",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003e= 2.0.0, \u003c 2.16.1"
                  },
                  {
                    "status": "affected",
                    "version": "\u003e= 3.0.0, \u003c 3.0.12"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12."
          }
        ],
        "id": "CVE-2026-85720",
        "lastModified": "2026-09-17T17:16:51.200",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.9,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 3.6,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-17T17:16:51.200",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/AsyncHttpClient/async-http-client/commit/d07dbc79f5cf378f63c246f6101d7579ace55acc"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/AsyncHttpClient/async-http-client/pull/2234"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Received",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-319"
              },
              {
                "lang": "en",
                "value": "CWE-522"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}

FKIE_CVE-2026-85720

Vulnerability from fkie_nvd - Published: 2026-09-17 17:16 - Updated: 2026-09-17 17:16

Severity

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

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6
	security-advisories@github.com	https://github.com/AsyncHttpClient/async-http-client/commit/d07dbc79f5cf378f63c246f6101d7579ace55acc
	security-advisories@github.com	https://github.com/AsyncHttpClient/async-http-client/pull/2234
	security-advisories@github.com	https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "async-http-client",
          "vendor": "AsyncHttpClient",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.16.1"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.0.12"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, a request using an HTTP proxy to reach an HTTPS origin can expose preemptive origin credentials because NettyRequestFactory and NettyRequestSender.sendRequestWithNewChannel attach Authorization to the plaintext CONNECT request before the TLS tunnel exists. Basic or Digest credentials and per-connection NTLM, Kerberos, or SPNEGO tokens intended for the origin are therefore visible to the proxy and to observers on the client-to-proxy hop. The tunneled request still receives origin Authorization after the tunnel is established, while Proxy-Authorization remains on CONNECT for its intended proxy recipient. This issue is fixed in versions 2.16.1 and 3.0.12."
    }
  ],
  "id": "CVE-2026-85720",
  "lastModified": "2026-09-17T17:16:51.200",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 3.6,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-17T17:16:51.200",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/AsyncHttpClient/async-http-client/commit/d07dbc79f5cf378f63c246f6101d7579ace55acc"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/AsyncHttpClient/async-http-client/pull/2234"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-319"
        },
        {
          "lang": "en",
          "value": "CWE-522"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

GHSA-XR57-GCX8-52HF

Vulnerability from github – Published: 2026-09-17 17:19 – Updated: 2026-09-17 17:19

Summary

AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request

Details

Impact

When a request uses an HTTP proxy to reach an HTTPS origin, the client opens the tunnel with a plaintext CONNECT sent to the proxy before any TLS exists. On affected versions the origin's preemptive credentials were added to that CONNECT. A Basic realm sent Authorization: Basic base64(user:pass) to the proxy in the clear, and NTLM, SPNEGO or Kerberos realms sent their token. The proxy, and anyone who can read the client to proxy hop, saw credentials that were meant only for the origin.

Affected versions

3.x: up to and including 3.0.11
2.x: up to and including 2.16.0

Patches

Fixed in 3.0.12 on the 3.x line and in 2.16.1 on the 2.x line. The origin Basic or Digest Authorization is no longer put on the CONNECT; it is added to the tunnelled request once the tunnel is up. The per-connection NTLM, Kerberos and SPNEGO token is likewise no longer attached on the tunnel path; it never reached the origin there in any case, and the challenge flow still negotiates it inside the tunnel.

Workarounds

Do not use preemptive origin authentication together with an HTTP proxy, or reach the origin without a CONNECT proxy.

Details

NettyRequestFactory added the origin Authorization to every request it built, including the CONNECT, and NettyRequestSender did the same for the per-connection NTLM or SPNEGO token in sendRequestWithNewChannel. Both now skip the CONNECT.

Note that 3.0.12 is itself affected by a separate issue, GHSA-rqf5-2wxv-rjf4, where a Digest challenge the client cannot read downgrades to Basic and sends the password in cleartext. Upgrade to 3.0.13 to pick up both fixes.

Severity

5.9 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.0.11"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.asynchttpclient:async-http-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 2.16.0"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.asynchttpclient:async-http-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "2.16.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-85720"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-319",
      "CWE-522"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-17T17:19:12Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\nWhen a request uses an HTTP proxy to reach an HTTPS origin, the client opens the tunnel with a plaintext CONNECT sent to the proxy before any TLS exists. On affected versions the origin\u0027s preemptive credentials were added to that CONNECT. A Basic realm sent `Authorization: Basic base64(user:pass)` to the proxy in the clear, and NTLM, SPNEGO or Kerberos realms sent their token. The proxy, and anyone who can read the client to proxy hop, saw credentials that were meant only for the origin.\n\n### Affected versions\n* 3.x: up to and including 3.0.11\n* 2.x: up to and including 2.16.0\n\n### Patches\nFixed in 3.0.12 on the 3.x line and in 2.16.1 on the 2.x line. The origin Basic or Digest Authorization is no longer put on the CONNECT; it is added to the tunnelled request once the tunnel is up. The per-connection NTLM, Kerberos and SPNEGO token is likewise no longer attached on the tunnel path; it never reached the origin there in any case, and the challenge flow still negotiates it inside the tunnel.\n\n### Workarounds\nDo not use preemptive origin authentication together with an HTTP proxy, or reach the origin without a CONNECT proxy.\n\n### Details\nNettyRequestFactory added the origin Authorization to every request it built, including the CONNECT, and NettyRequestSender did the same for the per-connection NTLM or SPNEGO token in sendRequestWithNewChannel. Both now skip the CONNECT.\n\nNote that 3.0.12 is itself affected by a separate issue, GHSA-rqf5-2wxv-rjf4, where a Digest challenge the client cannot read downgrades to Basic and sends the password in cleartext. Upgrade to 3.0.13 to pick up both fixes.",
  "id": "GHSA-xr57-gcx8-52hf",
  "modified": "2026-09-17T17:19:12Z",
  "published": "2026-09-17T17:19:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/AsyncHttpClient/async-http-client/security/advisories/GHSA-xr57-gcx8-52hf"
    },
    {
      "type": "WEB",
      "url": "https://github.com/AsyncHttpClient/async-http-client/pull/2234"
    },
    {
      "type": "WEB",
      "url": "https://github.com/AsyncHttpClient/async-http-client/commit/9dba5ac988b7e750551f59b2eab550b60ac8a0d6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/AsyncHttpClient/async-http-client"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-85720 (GCVE-0-2026-85720)

FKIE_CVE-2026-85720

GHSA-XR57-GCX8-52HF

Impact

Affected versions

Patches

Workarounds

Details

Tags

Sightings

Nomenclature

Related by attack behaviour