async-http-client vulnerability

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Prior to 3.0.13 and 2.16.1, cross-host request replay updates the current request but leaves the target request and related proxy context pointing at the original origin. Connection-pool selection, CONNECT handling, realm selection, and TLS setup can consequently send the original host's path, Host header, Authorization credentials, or plaintext request to the replay destination. Documented ResponseFilter failover and retry paths can trigger the replay. This issue is fixed in versions 3.0.13 and 2.16.1.

Published 7 Oct 2026Updated 10 Oct 20265 sources
CVSS 9.4

What happened

The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. Prior to 3.0.13 and 2.16.1, cross-host request replay updates the current request but leaves the target request and related proxy context pointing at the original origin. Connection-pool selection, CONNECT handling, realm selection, and TLS setup can consequently send the original host's path, Host header, Authorization credentials, or plaintext request to the replay destination. Documented ResponseFilter failover and retry paths can trigger the replay. This issue is fixed in versions 3.0.13 and 2.16.1.

Affected versions

async-http-client: >= 3.0.0, < 3.0.13; >= 2.0.0, < 2.16.1 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

  • Apply vendor-provided updates or mitigations.
  • Review affected product exposure and access logs.

Public PoC references

No public PoC reference has passed the current publication threshold.