Description

HCL AION is affected by a vulnerability where the Cross-Origin-Embedder-Policy (COEP) header was missing or insecure, so embedded cross-origin resources were not required to explicitly grant permission. This weakens cross-origin isolation, potentially resulting in unintended behavior or security impact under certain conditions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.2",
  "pubDate": "2026-11-06T14:17:12.987Z",
  "pubdate": "2026-11-06T14:17:12.987Z",
  "executiveSummary": "HCL AION contains a vulnerability related to the absence or improper configuration of the Cross-Origin-Embedder-Policy (COEP) HTTP response header. This misconfiguration leads to a failure in enforcing strict cross-origin isolation within the browser context.\nThe vulnerability type is categorized as a security configuration weakness. The lack of proper COEP enforcement permits embedded cross-origin resources to be loaded without explicit permission from the source server. This weakens the browser's ability to restrict document access to cross-origin data, effectively bypassing the protections intended by the Cross-Origin Isolation security model.\nThe impact involves an increased attack surface for cross-origin attacks, such as Spectre-style side-channel attacks or data exfiltration, if combined with other site-isolation bypasses. The affected system is HCL AION. There are no authentication requirements for an attacker to benefit from the lack of this header, as the vulnerability is inherent to the response delivered by the server to any client browser. Exploitation does not require specific user privileges but relies on the victim's browser context to interact with malicious or compromised cross-origin content.",
  "technicalDetails": "The root cause of this vulnerability is the failure of the HCL AION web server implementation to include or enforce the 'Cross-Origin-Embedder-Policy' (COEP) HTTP header. COEP is a critical security directive used to prevent a document from loading cross-origin resources that do not explicitly grant permission via the Cross-Origin-Resource-Policy (CORP) header or Cross-Origin-Resource-Sharing (CORS).\nIn a secure browser environment, COEP, when set to 'require-corp', ensures that resources like images, scripts, or iframes only load if they explicitly opt-in to being embedded. By omitting this header, HCL AION allows the browser to default to a legacy behavior where cross-origin assets are loaded without restriction. This configuration state prevents the browser from achieving the 'cross-origin isolated' state, which is a prerequisite for utilizing high-resolution performance timers (e.g., performance.now()) and other sensitive features that are otherwise restricted to mitigate side-channel attacks.\nThe attack flow proceeds as follows: An attacker identifies that HCL AION responses lack the COEP header. The attacker then hosts a malicious resource on a different origin. Since the HCL AION application does not enforce isolation, it will successfully embed the attacker-controlled resource. Once embedded, the lack of isolation allows the attacker to leverage side-channel primitives—such as speculative execution attacks (e.g., Spectre)—to read sensitive data from the process memory associated with the application's origin.\nThe vulnerability is present in the server-side response headers of HCL AION. The exposure is network-wide, as any client browser accessing the HCL AION instance will receive these headers, regardless of authentication status. There are no privilege requirements to exploit the absence of this header, as the vulnerability resides in the transport layer configuration. Post-exploitation, an attacker may succeed in bypassing cross-origin security boundaries, potentially leading to unauthorized data access, cross-site leaks, or the exfiltration of sensitive information processed within the application's memory space, depending on the capabilities of the browser and the presence of other security primitives."
}