CVE-2025-9633 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the LH Signing plugin for WordPress, developed by shawfactor. This vulnerability exists in all versions up to and including 2.83 due to missing or incorrect nonce validation in the plugin_options function. Nonces are security tokens used to verify that requests are intentional and originate from legitimate users. The absence or improper implementation of nonce validation allows an unauthenticated attacker to craft malicious requests that, when executed by an authenticated site administrator (e.g., by clicking a malicious link), can modify the plugin's settings without the administrator's consent. This type of attack exploits the trust a web application places in the user's browser and session, leveraging the administrator's privileges to alter plugin configurations. The vulnerability has a CVSS 3.1 base score of 4.3, indicating a medium severity level. The attack vector is network-based with low attack complexity, requires no privileges, but does require user interaction (the administrator must be tricked into performing an action). The impact is limited to integrity, as confidentiality and availability are not affected. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was published on September 11, 2025, and is cataloged under CWE-352, which specifically addresses CSRF issues.

For European organizations using WordPress sites with the LH Signing plugin, this vulnerability poses a risk primarily to the integrity of plugin configurations. An attacker could manipulate plugin settings, potentially weakening security controls or enabling further exploitation paths. While the vulnerability does not directly compromise data confidentiality or availability, unauthorized changes to plugin settings could lead to degraded security posture or facilitate subsequent attacks such as privilege escalation or data tampering. Organizations relying on this plugin for document signing or authentication features may face operational disruptions or compliance issues if plugin settings are altered maliciously. Given that the attack requires tricking an administrator into clicking a malicious link, the threat is more significant in environments where administrators have high privileges and may be targeted via spear-phishing or social engineering campaigns. The medium severity score reflects a moderate risk, but the potential for cascading effects in sensitive or regulated environments (e.g., financial, governmental, or healthcare sectors) in Europe could be substantial if exploited.

1. Immediate mitigation should include disabling the LH Signing plugin until a secure patched version is released. 2. Monitor official shawfactor and WordPress plugin repositories for updates and apply patches promptly once available. 3. Implement web application firewalls (WAFs) with rules to detect and block suspicious CSRF attempts targeting the plugin's endpoints. 4. Educate site administrators on the risks of clicking unsolicited links, especially those that could trigger administrative actions. 5. Employ Content Security Policy (CSP) headers and SameSite cookie attributes to reduce CSRF risks. 6. Conduct regular audits of plugin settings and logs to detect unauthorized changes. 7. Consider implementing multi-factor authentication (MFA) for administrative accounts to reduce the risk of session hijacking or unauthorized access. 8. For organizations with custom WordPress deployments, review and harden nonce validation mechanisms across all plugins and themes to prevent similar vulnerabilities.