CVE-2026-62136 in Flexible Quantity Plugin
Summary
by MITRE • 09/11/2026
Unauthenticated Broken Access Control in Flexible Quantity – Measurement Price Calculator for WooCommerce <= 2.3.21 versions.
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Analysis
by VulDB Data Team • 09/11/2026
The vulnerability identified as an unbroken access control flaw within the Flexible Quantity measurement price calculator plugin for WordPress, specifically affecting versions up to and including 2.3.21, represents a critical security deficiency in how user permissions are validated during product pricing calculations. This issue stems from the application's failure to enforce proper authorization checks on server-side endpoints responsible for processing dynamic pricing requests. In modern web applications, particularly those built on content management systems like WordPress that rely heavily on AJAX-driven interactions for real-time updates, it is imperative that every state-changing or data-retrieving request verifies that the initiating user possesses the requisite privileges. The absence of such verification allows any individual with network access to interact directly with these internal calculation mechanisms without requiring authentication or valid session tokens. This architectural oversight effectively bypasses standard security boundaries designed to restrict sensitive operations to authenticated users only, thereby exposing underlying business logic and potentially confidential pricing data to unauthorized parties.
From a technical perspective, the flaw resides in the handling of HTTP requests directed at specific AJAX action hooks associated with the plugin's calculation engine. When a client submits parameters defining product quantities or measurement units, the server processes these inputs to compute final prices but fails to validate whether the requester is an authenticated user or possesses administrative capabilities if such actions are intended for internal use only. This lack of input validation combined with insufficient access control creates a scenario where attackers can manipulate pricing variables remotely. By crafting specific HTTP POST requests containing manipulated quantity values, measurement units, or product identifiers, an attacker can force the server to execute calculations that may reveal sensitive information about discount structures, bulk pricing tiers, or internal cost margins. Furthermore, depending on how the calculated results are returned and displayed within the application's response payload, this vulnerability could potentially lead to broader impacts beyond mere data exposure, including potential denial of service if complex mathematical operations are triggered repeatedly by malicious actors aiming to exhaust server resources.
The operational impact of this broken access control is significant for both e-commerce businesses relying on WordPress and their customers. For merchants, the immediate consequence involves the unauthorized disclosure of proprietary pricing strategies. Competitors or malicious users can scrape bulk discount rates, wholesale price lists, or special offer structures that are typically hidden from public view to maintain competitive advantage. This leakage undermines business integrity and can lead to financial losses if competitors adjust their own pricing models accordingly. Additionally, while primarily an information disclosure issue in its current manifestation, the ability to interact with unauthenticated endpoints opens the door for further exploitation vectors. Attackers might leverage this access to probe for other vulnerabilities within the same plugin or related WordPress core files by observing error messages or response times associated with malformed inputs. In severe cases, if the calculation logic interacts directly with database queries without proper sanitization in conjunction with these unauthorized calls, it could escalate into SQL injection attacks, although the primary classification remains focused on access control failures.
To mitigate this vulnerability and secure the affected environment, immediate remediation steps must be taken by updating the Flexible Quantity measurement price calculator plugin to version 2.3.22 or later, where the developers have implemented proper authentication checks for all AJAX endpoints. It is crucial to verify that no older versions remain active on any production servers, as legacy code may still contain exploitable logic even if newer features are enabled. Administrators should also review server-side logs to identify potential exploitation attempts prior to patching, which can provide valuable intelligence regarding the scope of exposure and whether sensitive data was exfiltrated. Implementing a Web Application Firewall with rules specifically targeting unauthorized AJAX requests for known vulnerable plugins can serve as an effective compensating control while updates are being deployed across the infrastructure. Furthermore, adopting a principle of least privilege in server configurations ensures that even if similar vulnerabilities exist in other components, their impact is contained by restricting network-level access to administrative interfaces and internal API endpoints from untrusted networks.
This incident aligns with Common Weakness Enumeration identifier CWE-284, which describes Improper Access Control, highlighting the failure to restrict resources or functions based on user roles. It also maps closely to MITRE ATT&CK technique T1078, Valid Accounts, although in this specific case, it applies more accurately to unauthenticated access where no valid account is required due to the missing check entirely. Understanding these mappings helps security teams categorize the risk correctly within their vulnerability management programs and prioritize remediation efforts based on industry-standard frameworks. Continuous monitoring for similar patterns across all installed plugins is recommended to prevent recurrence of such authorization bypasses, ensuring that future updates adhere strictly to secure coding practices regarding input validation and access control enforcement.