CVE-2026-89190 in Robin Image Optimizer Plugin
Summary
by MITRE • 09/30/2026
The Robin Image Optimizer WordPress plugin before 2.0.8 does not check the user's capabilities before dispatching one of its bundled admin framework's request handlers, allowing users with a subscriber-level account to render admin-only Robin Image Optimizer WordPress plugin before 2.0.8 pages and disclose the Robin Image Optimizer WordPress plugin before 2.0.8's stored settings.
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Analysis
by VulDB Data Team • 09/30/2026
The vulnerability identified in Robin Image Optimizer versions prior to 2.0.8 represents a critical failure in access control mechanisms within the WordPress ecosystem. This flaw stems from an improper implementation of capability checks, specifically affecting how the plugin handles requests directed at its bundled admin framework. In secure software architecture, any endpoint or handler that exposes administrative functionality must strictly verify that the initiating user possesses the necessary privileges to perform such actions. However, in this specific instance, the code fails to validate whether the authenticated user holds an administrator role before processing these requests. This oversight creates a significant security gap where the distinction between public-facing content and restricted administrative interfaces is effectively neutralized for lower-privileged users.
The technical nature of this flaw aligns with CWE-285, which describes Improper Authorization vulnerabilities. By neglecting to enforce server-side authorization checks on specific request handlers within its admin framework, the plugin allows any authenticated user, regardless of their assigned role in WordPress, to interact with features intended exclusively for site administrators. This is particularly concerning because it bypasses the standard security model where capabilities like manage_options or edit_plugins are required to access sensitive configuration areas. The absence of these checks means that the application logic proceeds to execute administrative functions without confirming the user's identity and permission level, leading directly to unauthorized information disclosure.
The operational impact of this vulnerability is severe for WordPress site owners who rely on Robin Image Optimizer for managing image assets. Users with subscriber-level accounts or any other low-privilege role can exploit this flaw to access admin-only pages within the plugin interface. The primary consequence is the exposure of stored settings, which may include sensitive configuration details such as API keys, optimization parameters, database connection strings, or paths to internal resources. This disclosure not only compromises the confidentiality of the site's operational data but also potentially aids attackers in crafting more targeted exploits against the underlying WordPress installation and its associated services. The ability for low-privileged users to view these settings undermines the principle of least privilege and can lead further into lateral movement within a compromised environment.
From an offensive security perspective, this vulnerability maps directly to ATT&CK technique T1078, Valid Accounts, specifically in the context of using legitimate credentials with insufficient privileges that are then escalated through misconfiguration or logic flaws to access restricted resources. It also relates to T1530, Data from Cloud Storage Object Discovery, if the disclosed settings involve cloud-based image storage configurations. The exploitation requires no special tools beyond a standard web browser and valid login credentials for any user account on the target WordPress site, making it highly accessible to threat actors who have already gained initial access through phishing or other entry points.
To mitigate this risk, immediate action is required by updating the Robin Image Optimizer plugin to version 2.0.8 or later, where these authorization checks have been properly implemented. Site administrators should also audit their user roles and ensure that only trusted individuals are assigned subscriber-level accounts with access to the WordPress dashboard. Implementing Web Application Firewalls can provide an additional layer of defense by monitoring for anomalous requests targeting admin endpoints from low-privilege users. Furthermore, regular security audits focusing on capability checks in custom plugins will help prevent similar authorization bypasses in future developments or other third-party extensions used within the same environment.