CVE-2026-85720: Async http client AsyncHttpClient Sends Origin Credentials To Vulnerability

MODERATE
Advisory Identifier: GHSA-xr57-gcx8-52hf
CVSS 5.9
CWE-319 CWE-522
Published
Advisory Summary

CVE-2026-85720 is a MODERATE (CVSS 5.9) asynchttpclient sends origin credentials to vulnerability (CWE-319: Cleartext Transmission of Sensitive Information) affecting Async http client libraries in the Maven ecosystem. The issue involves asynchttpclient sends origin credentials to the proxy on the plaintext connect request. Remediation is available by upgrading affected packages to version 3.0.12, 2.16.1.

CVE-2026-85720 at a Glance

CVE Identifier CVE-2026-85720
GHSA Identifier GHSA-xr57-gcx8-52hf
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-319: Cleartext Transmission of Sensitive Information
Affected Product Async http client
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-85720

To remediate this vulnerability, upgrade all affected Async http client dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

org.asynchttpclient:async-http-client fixed: 3.0.12
<dependency>
    <groupId>org.asynchttpclient</groupId>
    <artifactId>async-http-client</artifactId>
    <version>3.0.12</version>
</dependency>
org.asynchttpclient:async-http-client fixed: 2.16.1
<dependency>
    <groupId>org.asynchttpclient</groupId>
    <artifactId>async-http-client</artifactId>
    <version>2.16.1</version>
</dependency>
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

mvn dependency:tree -Dincludes=org.asynchttpclient

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-85720, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree -Dincludes=org.asynchttpclient

Analyze the terminal output to locate any version of Async http client in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.0.12), your application is affected.

Note: The mvn dependency:tree -Dincludes=org.asynchttpclient command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-319: Cleartext Transmission of Sensitive Information, where the product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors. In Async http client, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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.

CVE-2026-85720 Affected Async http client Versions

2 component(s)
Fixed Versions:
3.0.122.16.1
Product / Package Ecosystem Affected Versions Fixed Version
org.asynchttpclient:async-http-client
Maven
≥ 3.0.0
< 3.0.12
3.0.12
org.asynchttpclient:async-http-client
Maven
≥ 2.0.0
< 2.16.1
2.16.1

References

Frequently Asked Questions

What is CVE-2026-85720?
CVE-2026-85720 is a security vulnerability in Async http client involving AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request under CWE-319: Cleartext Transmission of Sensitive Information.
Which Async http client versions are affected?
Affected versions include releases prior to 3.0.12, 2.16.1 across affected packages: org.asynchttpclient:async-http-client.
What version fixes CVE-2026-85720?
Upgrading to 3.0.12, 2.16.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is async-http-client affected?
Yes, org.asynchttpclient:async-http-client is affected in releases prior to 3.0.12, 2.16.1. Upgrade your dependency to 3.0.12, 2.16.1 or later.
What is the CVSS score of CVE-2026-85720?
CVE-2026-85720 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-85720?
CVE-2026-85720 is classified under CWE-319: Cleartext Transmission of Sensitive Information (The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors.).
How can I check Maven dependencies for CVE-2026-85720?
Run the dependency tree command: 'mvn dependency:tree -Dincludes=org.asynchttpclient'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xr57-gcx8-52hf",
  "modified" : "2026-09-17T17:19:12Z",
  "published" : "2026-09-17T17:19:12Z",
  "aliases" : [ "CVE-2026-85720" ],
  "summary" : "AsyncHttpClient sends origin credentials to the proxy on the plaintext CONNECT request",
  "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'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.\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.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.asynchttpclient:async-http-client"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "3.0.12"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.0.11"
    }
  }, {
    "package" : {
      "ecosystem" : "Maven",
      "name" : "org.asynchttpclient:async-http-client"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0"
      }, {
        "fixed" : "2.16.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.16.0"
    }
  } ],
  "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"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-319", "CWE-522" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-17T17:19:12Z",
    "nvd_published_at" : null
  }
}