CVE-2026-35104 in AION
Summary
by MITRE • 11/06/2026
HCL AION is affected by an open redirect vulnerability on the user registration page (Signup component). The redirect performed after registration used the value of the 'redirect' query parameter without validation, so a crafted registration link could send a user to an untrusted external site. This may be used in phishing attacks, potentially resulting in unintended behavior or security impact under certain conditions.
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Analysis
by VulDB Data Team • 11/06/2026
The vulnerability identified within HCL AION represents a classic open redirect flaw located specifically on the user registration interface, commonly referred to as the Signup component. In web application architecture, it is standard practice for applications to allow users to specify where they should be directed after completing an authentication or registration process. This functionality typically relies on query parameters such as 'redirect' which are appended to the login URL by developers to facilitate seamless user experience flows. However, in this specific instance, the implementation fails to perform any validation or sanitization of the value provided within this parameter before executing the redirection logic. Consequently, an attacker can craft a malicious registration link that includes a target URL pointing to an external domain controlled by the adversary rather than a legitimate internal page of the application.
From a technical perspective, the core defect lies in the absence of input validation on server-side redirect targets. When a user submits their credentials or completes the signup form, the backend logic retrieves the 'redirect' parameter and immediately issues an HTTP response with a status code indicating redirection to that specific URL. Because there is no whitelist check against trusted domains nor any encoding of special characters that might bypass client-side protections, the browser blindly follows the instruction provided by the server. This behavior effectively allows an attacker to leverage the trust users place in the HCL AION domain name. Since the phishing link originates from a legitimate and recognized source, victims are significantly more likely to click on it without suspicion compared to links coming from unknown or suspicious domains.
The operational impact of this vulnerability is primarily centered around social engineering attacks, particularly phishing campaigns. An attacker can distribute these crafted URLs through email, instant messaging platforms, or other communication channels under the guise of a legitimate account verification step. Once the victim interacts with the malicious link and completes the registration process, they are seamlessly redirected to a fraudulent website designed to mimic another service or steal additional credentials. This technique is highly effective because it bypasses many browser-based security warnings that typically flag untrusted domains. The resulting security impact includes potential credential theft, session hijacking if combined with other vulnerabilities, or malware distribution via the landing page of the phishing site.
This vulnerability aligns directly with CWE-601, which defines Open Redirect as a flaw where an application redirects users to URLs provided by user input without proper validation. Furthermore, in terms of offensive security frameworks such as MITRE ATT&CK, this behavior facilitates techniques associated with Phishing and Initial Access vectors like T1583 Acquire Infrastructure or T1078 Valid Accounts if the redirect leads to a credential harvesting page that successfully captures login data. The exploitation chain relies heavily on user interaction rather than automated code execution, making it less detectable by traditional intrusion detection systems but highly dangerous in targeted social engineering contexts.
To mitigate this vulnerability, developers must implement strict validation mechanisms for all redirect parameters. The most robust approach is to maintain a whitelist of allowed domains or paths that the application can safely redirect users to after registration. Any input not matching these predefined safe values should be rejected or defaulted to a known internal page rather than being passed through directly. Alternatively, if dynamic redirection is required, developers should encode the target URL and validate its structure against expected patterns before processing it on the server side. It is also advisable to use relative paths for redirects whenever possible, as browsers handle these more securely by defaulting them to the current domain context. Regular security code reviews and automated static analysis tools configured to detect open redirect patterns can further help in identifying and preventing such flaws during the development lifecycle.