CVE-2024-30127 is a medium-severity vulnerability identified in HCL Software's HCL Leap product, specifically affecting versions prior to 9.3.9. The vulnerability arises due to the absence of "no cache" HTTP headers in responses generated by HCL Leap. This omission allows sensitive information processed or displayed by the application to be stored in client-side or intermediary caches such as browser caches, proxy caches, or other caching mechanisms. The core issue is classified under CWE-524, which refers to the use of caches containing sensitive information without proper controls. When sensitive data is cached improperly, it can be accessed by unauthorized users who gain access to the cached data, either on the client device or on shared network infrastructure. This can lead to information disclosure, compromising confidentiality. The vulnerability does not require authentication or user interaction to be exploited, as it depends on how HTTP responses are handled by clients or intermediaries. There are no known exploits in the wild at the time of publication, and no official patches have been released yet. However, the risk remains that attackers could leverage this vulnerability to retrieve sensitive data from caches, especially in environments where multiple users share devices or network resources. The vulnerability affects all deployments of HCL Leap versions earlier than 9.3.9, which is a low-code application development platform often used by enterprises for rapid application delivery. The lack of cache control headers is a common but critical oversight that can lead to unintended data exposure.

For European organizations using HCL Leap, this vulnerability poses a risk of sensitive data leakage through cached content. This can include personally identifiable information (PII), business-critical data, or authentication tokens if these are included in responses without proper cache control. The impact is particularly significant for sectors with strict data protection regulations such as GDPR, where unauthorized disclosure of personal data can lead to regulatory penalties and reputational damage. Organizations in finance, healthcare, government, and critical infrastructure sectors are especially vulnerable due to the sensitivity of the data handled. The vulnerability could facilitate lateral attacks if cached data is accessed by unauthorized users on shared devices or networks, potentially leading to further compromise. Although the vulnerability does not directly affect system availability or integrity, the confidentiality breach alone can have severe consequences. The absence of known exploits suggests a window of opportunity for organizations to remediate before active exploitation occurs. However, the ease of exploitation via standard HTTP caching mechanisms means that once exploited, the impact could be widespread within affected environments.

To mitigate this vulnerability, European organizations should immediately review their HCL Leap deployments and verify the version in use. Upgrading to version 9.3.9 or later, once available, is the primary remediation step. In the interim, organizations should implement the following specific measures: 1) Configure web servers and reverse proxies to add appropriate cache-control headers such as 'Cache-Control: no-store, no-cache, must-revalidate' and 'Pragma: no-cache' to all sensitive responses generated by HCL Leap applications. 2) Audit application code and workflows to ensure that sensitive information is not inadvertently included in responses that may be cached. 3) Educate users and administrators about the risks of shared device usage and encourage clearing browser caches regularly, especially on shared or public terminals. 4) Employ network-level controls to restrict caching on proxy servers or content delivery networks that handle HCL Leap traffic. 5) Monitor logs and network traffic for unusual access patterns that might indicate attempts to retrieve cached sensitive data. 6) Conduct penetration testing focused on cache-related data leakage to validate the effectiveness of implemented controls. These steps go beyond generic advice by focusing on both application-level and infrastructure-level controls tailored to HCL Leap environments.