CVE-2026-26081 in ALOHA
Summary
by MITRE • 07/20/2026
HAProxy Community Edition 3.0 through 3.3 before 3.3.3 lacks a length check for the NEW_TOKEN format. HAProxy Enterprise and ALOHA are also affected.
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Analysis
by VulDB Data Team • 07/20/2026
The vulnerability in HAProxy Community Edition versions 3.0 through 3.3 before 3.3.3 represents a critical security flaw that stems from insufficient input validation within the NEW_TOKEN format processing mechanism. This weakness allows adversaries to exploit malformed token structures that exceed expected length parameters, potentially leading to memory corruption and system instability. The issue affects not only the community edition but also HAProxy Enterprise and ALOHA products, indicating a widespread impact across the HAProxy product portfolio.
The technical root cause of this vulnerability lies in the absence of proper bounds checking for token length validation during the processing of NEW_TOKEN format data structures. When HAProxy receives input containing tokens that exceed predetermined size limits, the application fails to validate these lengths before proceeding with memory allocation and processing operations. This omission creates an environment where attackers can craft malicious inputs designed to trigger buffer overflows or other memory-related anomalies. The flaw specifically manifests when the system attempts to handle token data structures that surpass acceptable length thresholds, causing unpredictable behavior in the application's memory management routines.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more severe exploitation vectors. Attackers leveraging this weakness could cause denial of service conditions through controlled crashes or restarts of HAProxy instances, disrupting critical network traffic routing functions. In more sophisticated scenarios, the lack of length validation may open pathways for memory corruption attacks that could potentially allow privilege escalation or arbitrary code execution within the affected systems. The widespread nature of the affected versions means that numerous deployments across various environments remain at risk, particularly those handling high volumes of token-based authentication or session management.
Organizations should prioritize immediate remediation through patch updates to HAProxy 3.3.3 or later versions that address the missing length validation checks in NEW_TOKEN format processing. System administrators must also implement network-level monitoring to detect anomalous token patterns that might indicate exploitation attempts. Additional defensive measures include configuring input validation rules at proxy boundaries, implementing rate limiting for token processing operations, and establishing robust log analysis procedures to identify potential exploitation activities. The vulnerability aligns with CWE-129, which addresses "Improper Validation of Array Index," and may map to ATT&CK techniques involving privilege escalation through memory corruption or service disruption attacks. Regular security assessments should verify that all HAProxy installations have been updated and that proper input validation mechanisms are in place to prevent similar issues in future deployments.