CVE-2026-107281 AsyncHttpClient CVE debrief

Who should care

Defenders and administrators of Java applications using AsyncHttpClient for NTLM or Negotiate authentication should assess their exposure and prioritize upgrading to fixed versions to prevent potential security issues.

Why it matters

The vulnerability in AsyncHttpClient could lead to unauthorized actions if exploited. Defenders should verify their applications' versions and upgrade to prevent potential security issues.

• Potential unauthorized actions on the server side due to connection reuse
• Need to verify and upgrade to fixed versions of AsyncHttpClient
• Review of authentication configurations for NTLM and Negotiate

Technical summary

The AsyncHttpClient library did not properly account for the authenticated principal in the connection pool key for NTLM and Negotiate authentication methods. This oversight allowed a connection authenticated for one principal to be reused for requests made under a different principal, potentially leading to unauthorized actions on the server side. The vulnerability affects versions prior to 3.0.13 and 2.16.1, and defenders should prioritize verifying if their applications use vulnerable versions and upgrading to fixed versions to prevent potential unauthorized actions.

Defensive priority

Defenders should prioritize verifying if their applications use vulnerable versions of AsyncHttpClient and upgrading to fixed versions (3.0.13 or 2.16.1) to prevent potential unauthorized actions.

Recommended defensive actions

• Verify if applications use vulnerable versions of AsyncHttpClient
• Upgrade to AsyncHttpClient version 3.0.13 or 2.16.1
• Review authentication methods and configurations for NTLM and Negotiate
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and fixed versions. However, there is limited information on actual exploitation or affected systems. Defenders should verify their applications' versions and configurations, focusing on NTLM and Negotiate authentication methods, and review potential security issues. Limited evidence is available, so thorough verification is necessary.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.