CVE-2025-6726 is a vulnerability identified in the Block Editor Gallery Slider plugin for WordPress, developed by krasenslavov. The issue stems from a missing authorization check in the function classic_gallery_slider_options(), which is responsible for handling certain post meta updates. This flaw allows authenticated users with Subscriber-level access or higher to modify limited post meta data for arbitrary posts without proper permission validation. Since WordPress roles like Subscriber typically have minimal privileges, this vulnerability effectively escalates their ability to alter content metadata beyond intended limits. The vulnerability affects all versions up to and including 1.1.1 of the plugin. The CVSS 3.1 base score is 4.3, indicating a medium severity level. The vector details reveal that the attack can be performed remotely (AV:N), requires low attack complexity (AC:L), needs privileges (PR:L) but no user interaction (UI:N), and impacts integrity only (I:L) without affecting confidentiality or availability. No known exploits are reported in the wild as of now, and no patches have been linked yet. The vulnerability is classified under CWE-862, which relates to missing authorization, a common security weakness where access controls are insufficient or absent, allowing unauthorized actions. Given the plugin’s role in managing gallery slider content, unauthorized modification of post meta could lead to content manipulation, defacement, or misleading presentation of media galleries on affected WordPress sites.

For European organizations using WordPress websites with the Block Editor Gallery Slider plugin, this vulnerability poses a risk of unauthorized content manipulation by low-privileged users or potentially compromised subscriber accounts. This could undermine the integrity of published content, damage brand reputation, and erode user trust. While the vulnerability does not directly expose sensitive data or cause service disruption, the ability to alter post metadata could be leveraged for misinformation, defacement, or embedding malicious links within galleries. Organizations in sectors such as media, e-commerce, education, and government that rely on WordPress for public-facing content may face reputational harm or indirect security risks if attackers exploit this flaw. Additionally, attackers could use this vulnerability as a foothold to escalate privileges further or conduct social engineering attacks by modifying visible content. The medium severity rating suggests a moderate risk, but the ease of exploitation by low-privileged users increases its practical threat level, especially in environments with many subscriber accounts or weak account management policies.

1. Immediate mitigation involves restricting Subscriber-level user capabilities and auditing user roles to ensure minimal necessary privileges are assigned. 2. Disable or remove the Block Editor Gallery Slider plugin if it is not essential to reduce attack surface. 3. Monitor and review post meta changes regularly for unauthorized modifications, especially focusing on gallery-related metadata. 4. Implement strong authentication and account management policies to prevent account compromise of low-privileged users. 5. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the classic_gallery_slider_options() function or related endpoints. 6. Follow the plugin vendor’s updates closely and apply patches as soon as they become available. 7. Consider using alternative gallery slider plugins with better security track records if timely patching is not feasible. 8. Conduct security awareness training for administrators to recognize signs of content tampering and respond promptly.