CVE-2023-28666 in InPost Gallery Plugin
Summary
by MITRE • 03/22/2023
The InPost Gallery WordPress plugin, in versions < 2.2.2, is affected by a reflected cross-site scripting vulnerability in the 'imgurl' parameter to the add_inpost_gallery_slide_item action, which can only be triggered by an authenticated user.
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Analysis
by VulDB Data Team • 12/07/2025
The InPost Gallery WordPress plugin vulnerability represents a critical security flaw that undermines the integrity of WordPress websites utilizing this specific plugin. This reflected cross-site scripting vulnerability exists within the plugin's handling of user input, specifically in the 'imgurl' parameter of the add_inpost_gallery_slide_item action. The vulnerability affects all versions prior to 2.2.2, indicating that the plugin developers identified and addressed this security concern in their subsequent releases. The flaw is particularly concerning because it operates within the WordPress admin interface, where privileged users interact with plugin functionality, making it a prime target for exploitation by malicious actors who have gained access to administrative accounts.
The technical implementation of this vulnerability stems from improper input validation and output sanitization within the plugin's backend processing. When an authenticated user submits a request containing malicious content in the 'imgurl' parameter, the plugin fails to adequately sanitize this input before incorporating it into the response. This reflected behavior occurs because the plugin directly echoes user-supplied data back to the browser without proper encoding or filtering mechanisms. The vulnerability classification aligns with CWE-79, which specifically addresses cross-site scripting flaws where untrusted data is reflected back to users without proper sanitization. The attack vector requires authentication, meaning that an attacker must first compromise a legitimate administrative account or gain access to a user with sufficient privileges to execute the malicious payload.
The operational impact of this vulnerability extends beyond simple data theft or website defacement, as it provides attackers with the capability to execute arbitrary JavaScript code within the context of an authenticated user's browser session. This could enable attackers to steal session cookies, modify plugin settings, access sensitive administrative functions, or even escalate privileges within the WordPress environment. The reflected nature of the vulnerability means that the malicious payload would be delivered through a crafted URL that, when visited by an authenticated user, would execute the attacker's code. This scenario is particularly dangerous in enterprise environments where administrators may inadvertently click on malicious links or where social engineering tactics are employed to trick users into executing the exploit. The vulnerability also aligns with ATT&CK technique T1566, which covers social engineering methods that can be used to gain initial access to systems before exploiting such administrative vulnerabilities.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected plugin to version 2.2.2 or later, which contains the necessary security fixes. Administrators should also implement additional security measures including regular security audits of installed plugins, monitoring for suspicious user activity, and implementing multi-factor authentication for administrative accounts. Network-level protections such as web application firewalls can provide additional layers of defense by detecting and blocking malicious requests containing known XSS patterns. Security monitoring should specifically track for unusual parameter values in plugin endpoints and implement strict access controls to limit the scope of potential exploitation. Organizations should also conduct regular security training for administrators to recognize phishing attempts and other social engineering methods that could be used to compromise accounts and subsequently exploit this vulnerability. The remediation process should include thorough testing of the updated plugin to ensure that security patches do not introduce compatibility issues with existing website functionality.