CVE-2021-45476 is a medium-severity reflected Cross-Site Scripting (XSS) vulnerability found in the Yordam Library Information Document Automation Program, a product developed by Yordam Informatics Systems. This vulnerability affects versions prior to 19.02. The flaw arises from improper neutralization of user-supplied input during web page generation, classified under CWE-79. Specifically, the vulnerability allows unauthenticated attackers to craft malicious URLs that, when visited by a user, cause the application to reflect and execute arbitrary JavaScript code within the victim's browser context. The CVSS 3.1 base score is 4.7, indicating a medium impact with the vector AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N. This means the attack can be launched remotely over the network without any privileges, requires low attack complexity, no authentication, but does require user interaction (clicking a malicious link). The scope is changed (S:C), indicating that the vulnerability affects resources beyond the vulnerable component, and the impact is limited to confidentiality (C:L) with no impact on integrity or availability. No known exploits are reported in the wild, and no patches have been linked in the provided data. The vulnerability could be exploited to steal sensitive information accessible via the browser, such as session tokens or personal data, or to perform actions on behalf of the user in the context of the affected web application. Given the nature of reflected XSS, the attack vector typically involves social engineering to entice users to click on malicious links.

For European organizations using the Yordam Library Information Document Automation Program, this vulnerability poses a risk primarily to confidentiality. Attackers could leverage the reflected XSS to steal session cookies or other sensitive information from users, potentially leading to unauthorized access or data leakage. Since the vulnerability is unauthenticated and remotely exploitable, any user accessing the vulnerable system could be targeted, increasing the attack surface. Libraries, academic institutions, and organizations managing document automation with this software could face reputational damage and compliance issues under GDPR if personal data is compromised. Although the vulnerability does not affect integrity or availability, the confidentiality breach could facilitate further attacks such as session hijacking or phishing campaigns. The requirement for user interaction means that successful exploitation depends on social engineering, but the low complexity and no authentication needed make it a viable threat. The lack of patches or mitigations at the time of publication increases the urgency for affected organizations to implement compensating controls.

1. Immediate mitigation should include implementing web application firewall (WAF) rules to detect and block reflected XSS attack patterns targeting the Yordam Library Information Document Automation Program. 2. Organizations should educate users about the risks of clicking on suspicious links, especially those purporting to come from internal library or document management systems. 3. Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of XSS attacks. 4. If possible, restrict access to the affected application to trusted networks or VPNs to limit exposure. 5. Monitor web server logs for unusual URL parameters or repeated suspicious requests that may indicate exploitation attempts. 6. Engage with Yordam Informatics Systems to obtain patches or updates; if unavailable, consider temporary replacement or isolation of the vulnerable system. 7. Conduct regular security assessments and penetration testing focused on input validation and output encoding to identify and remediate similar vulnerabilities proactively. 8. Implement strict input validation and output encoding in any custom integrations or extensions to the product to prevent injection of malicious scripts.