GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

GHSA-XR57-GCX8-52HF

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



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.