CVE-2023-6528 is a critical vulnerability identified in the Slider Revolution WordPress plugin versions prior to 6.6.19. The flaw is categorized under CWE-94, which refers to improper control of code generation, commonly known as code injection. Specifically, this vulnerability arises because the plugin does not adequately restrict users with at least Author role privileges from unserializing arbitrary content during the slider import process. Unserialization of untrusted data can lead to the execution of malicious code on the server. Since the Author role is a relatively low-privilege user role in WordPress, this vulnerability significantly lowers the barrier for exploitation. The vulnerability allows remote attackers to achieve remote code execution (RCE) without requiring user interaction, and with low attack complexity. The CVSS v3.1 score of 8.8 reflects the high severity, with network attack vector, low attack complexity, privileges required (Author role), no user interaction, and high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the potential for exploitation is substantial due to the widespread use of Slider Revolution, a popular WordPress plugin for creating sliders and visual content. The vulnerability affects all versions before 6.6.19, and no official patch links were provided in the data, indicating that users should urgently update to the latest version or apply vendor-provided mitigations once available. The risk is compounded by the fact that many WordPress sites use this plugin, and compromised sites could be leveraged for further attacks such as website defacement, data theft, or pivoting into internal networks.

For European organizations, the impact of CVE-2023-6528 can be severe. Many businesses, government agencies, and institutions in Europe rely on WordPress for their websites, and Slider Revolution is among the most popular plugins for enhancing site visuals and user experience. Exploitation of this vulnerability could lead to unauthorized remote code execution, allowing attackers to take full control of affected web servers. This can result in data breaches involving personal data protected under GDPR, leading to regulatory fines and reputational damage. Additionally, attackers could use compromised servers as a foothold to launch further attacks within corporate networks or to distribute malware and ransomware. The availability of the website could also be disrupted, impacting business continuity and customer trust. Given the Author role requirement, insider threats or compromised user accounts could accelerate exploitation. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the high severity score and ease of exploitation mean European organizations should act swiftly to prevent potential incidents.

1. Immediate update of the Slider Revolution plugin to version 6.6.19 or later, where the vulnerability is patched. 2. Restrict the assignment of the Author role and review user privileges to ensure only trusted users have such access, minimizing the risk of malicious import actions. 3. Implement web application firewalls (WAFs) with rules to detect and block suspicious unserialization attempts or unusual slider import activities. 4. Monitor WordPress logs and user activities for anomalous behavior related to slider imports or unexpected code execution. 5. Employ security plugins that can detect and prevent code injection attacks and unauthorized file modifications. 6. Regularly back up website data and configurations to enable rapid recovery in case of compromise. 7. Conduct security awareness training for site administrators and content creators about the risks of plugin vulnerabilities and the importance of timely updates. 8. If immediate patching is not possible, consider disabling the slider import functionality or limiting it to higher privilege roles temporarily.