CVE-2022-24717 is a cross-site scripting (XSS) vulnerability identified in the Finastra ssr-pages library, an HTML page builder designed for server-side rendering (SSR). The vulnerability exists in versions prior to 0.1.5 and arises due to improper neutralization of untrusted input provided to the `redirect.link` property when passed as an argument to the `build(MessagePageOptions)` function. Specifically, the library fails to adequately sanitize or encode this input, allowing an attacker to inject malicious scripts into the generated HTML pages. When a victim loads such a page, the injected script executes in their browser context, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. No known exploits have been reported in the wild, and no workaround is currently available other than upgrading to version 0.1.5 or later, where the issue has been patched. The vulnerability falls under CWE-79, which covers improper neutralization of input during web page generation, a common vector for XSS attacks. Given that ssr-pages is a component used in server-side rendering workflows, the impact depends on how and where it is integrated within applications, particularly those handling sensitive user data or authentication flows.

For European organizations, the impact of this vulnerability can be significant, especially for financial institutions, software vendors, and service providers that incorporate Finastra's ssr-pages in their web applications. Exploitation could lead to the compromise of user sessions, leakage of sensitive information, and unauthorized transactions or actions within affected applications. This is particularly critical in sectors with strict data protection regulations such as GDPR, where data breaches can result in heavy fines and reputational damage. Additionally, organizations relying on SSR for dynamic content generation may face risks of persistent XSS attacks, which can be used to distribute malware or conduct phishing campaigns targeting their user base. The absence of known exploits suggests limited active targeting so far, but the availability of a patch means attackers could develop exploits if systems remain unpatched. The medium severity rating reflects the fact that exploitation requires injection of malicious input into the vulnerable property, which may be constrained by application logic or access controls, but the potential consequences on confidentiality and integrity remain notable.

European organizations should prioritize upgrading all instances of Finastra ssr-pages to version 0.1.5 or later to apply the official patch that addresses this vulnerability. Beyond patching, developers should implement strict input validation and output encoding practices, especially for any user-controllable parameters involved in page rendering. Employing Content Security Policy (CSP) headers can help mitigate the impact of potential XSS by restricting script execution contexts. Security teams should conduct code reviews and penetration testing focused on SSR components to identify any residual or similar injection flaws. Monitoring web application logs for unusual redirect.link parameter values or anomalous user behavior can aid in early detection of exploitation attempts. Finally, organizations should ensure their incident response plans include procedures for handling XSS incidents, including user notification and remediation steps.