CVE-2026-84718 in Ansible Automation Platform
Summary
by MITRE • 09/23/2026
A flaw was found in the Ansible Automation Platform automation-controller. In the shipped production configuration, the Controller trusts the client-supplied X-Forwarded-For header as the request's client IP without verifying that it originated from a trusted proxy, and selects the leftmost (attacker-controlled) header value. As a result, an attacker can forge the source IP address recorded for their requests in the Controller's audit and access logs, degrading the integrity of forensic and SIEM attribution. The flaw does not grant additional access.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified within Ansible Automation Platform automation-controller represents a significant trust boundary violation regarding network identity verification. In standard web application architectures, particularly those deployed behind reverse proxies or load balancers, it is common practice to rely on the X-Forwarded-For HTTP header to determine the original client IP address. This header contains a comma-separated list of IP addresses representing each proxy that handled the request prior to reaching the final server. The security flaw lies in the Controller's implementation logic, which blindly trusts any value provided by the client in this header without performing validation against a predefined whitelist of trusted internal proxies. Furthermore, the application incorrectly selects the leftmost IP address from the list as the source identity. Since HTTP headers are easily spoofable by any entity capable of sending raw TCP packets to the service port, an attacker can manipulate this field at will. By placing their own forged IP address in the first position of the X-Forwarded-For header, the attacker ensures that the application records this fabricated value as the source of the request.
This misconfiguration directly impacts the integrity and reliability of security auditing mechanisms associated with the platform. The primary consequence is not an immediate compromise of confidentiality or availability through unauthorized access, but rather a degradation of forensic attribution capabilities. Security Information and Event Management systems rely heavily on accurate IP address logging to correlate events, detect anomalies, and attribute malicious activity to specific threat actors. When audit logs contain falsified source IPs, security teams lose the ability to accurately trace attacks back to their originators. This obfuscation technique allows attackers to evade detection by masking their true network location or impersonating trusted internal systems within log entries. While the flaw does not grant additional access privileges such as privilege escalation or remote code execution, it undermines the foundational trust required for effective security monitoring and incident response operations.
From a classification perspective, this vulnerability aligns with CWE-287, which describes Improper Authentication, specifically in contexts where identity is derived from untrusted input sources without proper validation. It also relates to CWE-913, as it involves the misuse of protocol elements that are intended for internal network communication rather than external client interaction. In terms of offensive security tactics, this behavior facilitates ATT&CK technique T1078, Valid Accounts or T1562, Impair Defenses, by allowing an adversary to obscure their presence and hinder log-based detection mechanisms. The lack of verification against a trusted proxy list indicates a failure in implementing the principle of least privilege regarding network trust relationships, where external inputs are treated with the same level of confidence as internal infrastructure signals.
To mitigate this vulnerability, administrators must configure Ansible Automation Platform to strictly validate the X-Forwarded-For header against a known set of trusted reverse proxies or load balancers that sit in front of the Controller. This typically involves updating application configuration files or environment variables to define an allowlist of IP addresses representing legitimate internal infrastructure. Requests originating from IPs not on this list should either have their X-Forwarded-For headers ignored, causing the system to fall back to the actual TCP connection source address, or be rejected entirely if such a fallback is deemed unsafe for other reasons. Additionally, deploying network-level controls such as ingress firewalls can prevent external entities from sending crafted HTTP requests directly to the application port, ensuring that only authorized proxy servers can modify these headers. Regular auditing of log integrity and correlation with actual connection logs should also be implemented to detect any ongoing attempts at IP spoofing or forensic obfuscation.