Critical Proxy Authentication Exposure in AsyncHttpClient Library
Summary
DEBIAN-CVE-2026-107285: The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Affects async-http-client versions 2.12.3-1 – 2.12.3-1+deb12u1. No fix is published. How to fix ↓
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Background
The AsyncHttpClient (AHC) library is a popular tool for Java applications, enabling them to execute HTTP requests and handle responses asynchronously. It is widely used due to its efficiency and ease of integration. However, prior to versions 3.0.12 and 2.16.1, AHC had a significant vulnerability related to proxy authentication, which could expose sensitive credentials.
Vulnerability Detail
The vulnerability arises from the handling of proxied WebSocket (ws) requests through the CONNECT method. The NettyRequestFactory.newNettyRequest and requestUri functions determine whether to attach proxy authentication based solely on the URI's security status. Since ws is not considered secure, the Proxy-Authorization header from the proxy is included in the tunneled WebSocket upgrade request sent to the origin server. This flaw allows attackers to recover basic credentials directly and potentially replay or crack Digest responses offline, posing a serious security risk.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, users can avoid using WebSocket connections over unsecured channels or implement additional security measures to protect sensitive data during transmission.
Conclusion
The AsyncHttpClient library has a critical vulnerability that can expose proxy authentication credentials through unsecured WebSocket requests. It is crucial for users to update to the latest patched versions to mitigate this risk. Additionally, utilizing tools like Vulert can help in monitoring and managing vulnerabilities effectively.
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FAQ
The CVSS score of this vulnerability is 5.9, indicating a moderate level of severity.
Versions prior to 3.0.12 and 2.16.1 are affected by this vulnerability.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The vulnerability can lead to the exposure of sensitive proxy authentication credentials, which can be exploited by attackers.
Yes, Vulert can monitor and alert you in real-time for open-source vulnerabilities in your software using just a manifest file like package-lock.json.
References
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