CVE-2026-82530 in Country Blocker Plugin
Summary
by MITRE • 09/09/2026
IP2Location Country Blocker plugin for WordPress before 2.45.0 contains an access control bypass vulnerability that allows unauthenticated remote attackers to circumvent IP-based restrictions by forging the X-Real-IP HTTP header. Attackers can set the X-Real-IP header to an allowlisted IP address to bypass page, link, or site-wide access restrictions and access otherwise-blocked resources.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified in the IP2Location Country Blocker plugin for WordPress prior to version 2.45.0 represents a critical failure in server-side input validation and trust boundary enforcement. This flaw specifically targets the mechanism used by web applications to determine client geographic location based on IP addresses, which is often utilized behind reverse proxies or load balancers that terminate SSL connections and forward original client information via specific HTTP headers such as X-Real-IP or X-Forwarded-For. In a properly secured architecture, these headers are typically set exclusively by trusted infrastructure components like Nginx or Apache to preserve the true source IP of the connecting user. However, in this vulnerable implementation, the plugin fails to verify whether the incoming request originated from a trusted proxy before trusting the values contained within the X-Real-IP header. This lack of validation allows any remote attacker who can send HTTP requests directly to the web server or through an untrusted intermediary to inject arbitrary IP addresses into these headers, effectively spoofing their geographic origin and network identity without needing valid credentials or physical proximity to the restricted networks.
From a technical perspective, this vulnerability is classified under CWE-287 Improper Authentication because it allows an attacker to bypass authentication mechanisms that rely on IP-based access control lists rather than user-specific credentials. Furthermore, it aligns with CWE-918 Server-Side Request Forgery (SSRF) principles in the context of trusting untrusted input for security decisions, and more specifically falls under CWE-602 Client-Side Injection of Server-Side Logic if viewed through the lens of manipulating server behavior via client-controlled data. The operational impact is severe as it enables unauthorized access to resources that are intended to be restricted based on geographic location or IP whitelist policies. Attackers can exploit this flaw to bypass page-level, link-level, or site-wide restrictions, potentially gaining access to administrative areas, sensitive user data, premium content, or internal APIs that were not meant for public consumption. This undermines the fundamental security model of geoblocking and IP whitelisting, rendering these protective measures ineffective against determined adversaries who understand how HTTP headers are processed by the underlying application logic.
The exploitation vector is straightforward yet potent, requiring only basic knowledge of HTTP request manipulation tools such as curl or Burp Suite to modify outgoing requests. By setting the X-Real-IP header to an IP address that matches a predefined allowlist within the plugin configuration, the attacker tricks the WordPress installation into believing they are connecting from a trusted location. This bypasses any subsequent checks that rely on this spoofed data for authorization decisions. The consequence is not merely theoretical; in real-world scenarios, such vulnerabilities have been leveraged to access restricted administrative dashboards, scrape proprietary content, or probe internal network structures by masking the attacker's true identity and location from logging systems that also depend on these headers for accurate attribution.
To mitigate this vulnerability, immediate action must be taken to upgrade the IP2Location Country Blocker plugin to version 2.45.0 or later where the issue has been addressed through stricter validation of header origins. In environments where upgrading is not immediately feasible, administrators should implement server-level configurations that strip untrusted X-Real-IP and X-Forwarded-For headers before they reach the PHP application layer. This can be achieved by configuring web servers like Nginx or Apache to only accept these headers from known internal proxy IP ranges and overwrite them with the actual client IP if received from external sources. Additionally, relying solely on IP-based access control is considered a weak security practice; organizations should augment such measures with multi-factor authentication for administrative accounts and ensure that sensitive resources are protected by robust identity verification mechanisms rather than network location alone. Regular auditing of plugin code for similar trust boundary violations and keeping all WordPress components updated to their latest secure versions remain essential practices in maintaining the integrity of web applications against header injection attacks.