CVE-2026-107228 in async-http-client
Summary
by MITRE • 10/08/2026
The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.1.0 until 3.0.14, the enabled-by-default cookie store replaces a Cookie header explicitly supplied through setHeader or addHeader whenever the store contributes any cookie for the origin. In a shared client, stored cookies originating from one user can replace a different user's request cookie, causing the request to execute under the wrong session. This bypasses the earlier CVE-2024-53990 remediation, which covered cookies supplied through addCookie but not a directly supplied header. This issue is fixed in version 3.0.14.
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Analysis
by VulDB Data Team • 10/08/2026
The AsyncHttpClient library serves as a foundational component for Java-based applications requiring efficient execution of HTTP requests and asynchronous processing of responses. A critical security flaw was identified within the cookie management logic spanning versions from 2.1.0 through 3.0.14, specifically affecting scenarios where clients are shared across multiple users or contexts. The vulnerability stems from an interaction between the library's default-enabled persistent cookie store and explicit header manipulation methods such as setHeader or addHeader. When a request is initiated using these methods to manually inject specific cookies via the Cookie HTTP header, the AsyncHttpClient logic checks if there are any stored cookies associated with the target origin. If such stored cookies exist, the implementation erroneously overwrites the explicitly provided Cookie header with the contents of the cookie store rather than merging or respecting the developer's explicit instruction.
This behavior creates a significant session hijacking and identity confusion risk in multi-tenant environments or applications where client instances are reused for different users. Because the library replaces the manually supplied cookies with those retrieved from the shared storage, an authenticated request intended to operate under one user's credentials may inadvertently execute using another user's stored session tokens. This effectively bypasses authentication controls by allowing a malicious actor who can influence cookie storage or exploit cross-user client sharing to impersonate other users. The impact is severe as it undermines the integrity of access control mechanisms that rely on accurate session identification, potentially leading to unauthorized data access and privilege escalation within the application context.
The vulnerability also represents a regression in security posture relative to earlier remediation efforts. A previous fix addressed CVE-2024-53990, which covered cases where cookies were added via the addCookie method but failed to account for scenarios involving direct header manipulation through setHeader or addHeader. This gap allowed attackers to circumvent prior safeguards by explicitly setting headers while relying on the library's internal cookie store logic to override them. The issue is fully resolved in version 3.0.14, which corrects the precedence rules so that explicit header values are preserved when provided directly by the application code, ensuring that manual overrides take priority over stored session data unless specifically intended otherwise by secure design patterns.
From a classification perspective, this flaw aligns with CWE-287 Improper Authentication and CWE-613 Insufficient Session Expiration, as it involves the mismanagement of authentication state leading to unauthorized access. In terms of adversary tactics, this vulnerability facilitates techniques associated with ATT&CK Tactic TA0004: Privilege Escalation and specifically relates to session hijacking behaviors where an attacker leverages existing valid credentials or sessions belonging to other users. To mitigate this risk in environments still running affected versions, developers should avoid sharing AsyncHttpClient instances across different user contexts unless strict isolation is enforced at the application level. Alternatively, applications can disable the default cookie store if persistent cookies are not required for their specific use case, thereby preventing the automatic injection of stored cookies that could override explicit header values. Upgrading to version 3.0.14 or later remains the most effective remediation strategy to eliminate this class of session confusion vulnerabilities entirely.