Description

HCL AION is affected by a vulnerability where user-controlled input could be included in HTTP response headers without proper neutralization of CR/LF characters. This may allow an attacker to inject headers or split responses, potentially resulting in unintended behavior or security impact under certain conditions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-11-06T14:17:11.360Z",
  "pubdate": "2026-11-06T14:17:11.360Z",
  "executiveSummary": "HCL AION is vulnerable to HTTP Response Splitting and Header Injection due to insufficient validation of user-controlled input incorporated into HTTP response headers.\nThe vulnerability occurs because the application fails to neutralize Carriage Return (CR) and Line Feed (LF) characters within data streams rendered in header fields.\nAn attacker can exploit this flaw to inject arbitrary HTTP headers, potentially leading to cross-site scripting (XSS), cache poisoning, session fixation, or the delivery of malicious content to the user's browser.\nThis vulnerability impacts the integrity of HTTP responses and may bypass security controls relying on predictable header structures.\nSuccessful exploitation requires the attacker to influence input that the application subsequently reflects in an HTTP header.\nThe risk is categorized as significant, as it enables attackers to manipulate the client-server communication process to deceive users or subvert downstream security mechanisms.",
  "technicalDetails": "The vulnerability resides in the way HCL AION processes user-supplied input before embedding it into outgoing HTTP response headers. HTTP protocol specifications define headers as line-terminated fields, typically separated by CRLF (ASCII 0x0D 0x0A) sequences. When an application fails to sanitize these control characters, it enables an attacker to prematurely terminate the intended header and inject new, arbitrary headers or even an entirely separate HTTP response body.\nThe root cause is the lack of strict character filtering or encoding routines for parameters that are dynamically rendered within HTTP header fields. By crafting input containing encoded or raw CRLF sequences, an attacker can manipulate the HTTP response stream.\nThe attack flow follows these steps: 1. Identification of an entry point where user-controllable input is reflected in an HTTP header; 2. Crafting of a payload containing injection sequences (e.g., %0D%0A followed by a malicious header like 'Set-Cookie:' or 'Location:'); 3. Submission of the request to the HCL AION server; 4. Processing of the tainted input by the application, which includes the injected characters directly into the header block; 5. The server sends a malformed HTTP response to the client.\nBy splitting the response, an attacker can effectively execute a 'response splitting' attack. If the server is positioned behind a caching proxy or load balancer, this injection can lead to cache poisoning, where the malicious response is stored and served to subsequent unsuspecting users. Furthermore, by injecting a secondary status line and headers, an attacker can simulate a different web page or redirect the user to a malicious domain, bypassing browser-side security policies such as Same-Origin Policy (SOP).\nExploitation is typically achieved via remote, unauthenticated network requests. The payload behavior is strictly defined by the attacker's ability to append lines to the protocol stream. Post-exploitation impact varies from local session hijacking through cookie manipulation to broader client-side compromise if arbitrary JavaScript is injected via 'Content-Type' or 'Content-Security-Policy' header overrides."
}