CVE-2025-0763 is a medium-severity vulnerability affecting the Ultimate Classified Listings plugin for WordPress, developed by webcodingplace. The vulnerability arises from a missing authorization check in the plugin's save_custom_fields function across all versions up to and including 1.6. This flaw allows any authenticated user with Subscriber-level access or higher to modify plugin custom fields without proper permission validation. Technically, the issue is categorized under CWE-862 (Missing Authorization), indicating that the plugin fails to verify whether the user has the necessary capabilities before allowing data modifications. Since WordPress Subscriber roles typically have minimal privileges, this vulnerability significantly lowers the attacker's bar to tamper with plugin data. The CVSS 3.1 base score is 4.3 (medium), reflecting that the attack vector is network-based (remote), requires low attack complexity, and only low privileges (authenticated user) are needed. No user interaction is required, and the impact is limited to integrity (modification of data) without affecting confidentiality or availability. No known exploits have been reported in the wild, and no patches are currently linked, suggesting that mitigation relies on vendor updates or manual code fixes. This vulnerability could be exploited by attackers who have gained subscriber-level access, possibly through credential stuffing, phishing, or other means, to alter classified listing data, potentially misleading users or damaging the website's credibility.

For European organizations using WordPress sites with the Ultimate Classified Listings plugin, this vulnerability poses a risk to data integrity within the plugin's scope. Attackers with low-level authenticated access can manipulate classified listing information, which could lead to misinformation, fraudulent listings, or reputational damage. While it does not directly compromise sensitive user data or site availability, the unauthorized modification of listings can undermine trust and potentially facilitate further attacks or scams. Organizations relying on classified listings for business operations, customer engagement, or community services may experience operational disruptions or loss of user confidence. Additionally, regulatory compliance under GDPR may be indirectly impacted if manipulated data leads to misinformation affecting users or customers. The vulnerability's exploitation could also serve as a foothold for privilege escalation or lateral movement within the WordPress environment if combined with other vulnerabilities.

To mitigate CVE-2025-0763, European organizations should: 1) Immediately audit WordPress installations to identify the presence of the Ultimate Classified Listings plugin and its version. 2) Restrict Subscriber-level user registrations or enforce stricter user verification to reduce the risk of unauthorized access. 3) Implement custom capability checks or patches in the plugin code to enforce authorization on the save_custom_fields function until an official patch is released. 4) Monitor and log changes to classified listings and plugin custom fields to detect unauthorized modifications promptly. 5) Employ Web Application Firewalls (WAFs) with rules targeting suspicious authenticated user behavior related to plugin data modifications. 6) Educate site administrators and users about the risks of credential compromise and enforce strong password policies and multi-factor authentication to limit attacker access. 7) Stay updated with vendor announcements for official patches and apply them promptly once available.