CVE-2022-3590 in WordPress
Summary
by MITRE • 12/14/2022
WordPress is affected by an unauthenticated blind SSRF in the pingback feature. Because of a TOCTOU race condition between the validation checks and the HTTP request, attackers can reach internal hosts that are explicitly forbidden.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/21/2025
The vulnerability identified as CVE-2022-3590 represents a critical security flaw within the WordPress content management system that exploits a blind server-side request forgery vulnerability through the pingback feature. This vulnerability specifically targets the pingback functionality that allows external systems to notify a WordPress site when it has been linked to by another website. The flaw manifests as an unauthenticated blind SSRF that leverages a time-of-check to time-of-use race condition, a well-documented pattern that creates exploitable timing gaps in validation processes. The vulnerability exists because WordPress performs initial validation checks on URLs before executing HTTP requests, but fails to maintain consistency between these checks and the actual execution phase.
The technical implementation of this vulnerability stems from the pingback feature's handling of URLs that are passed through the XML-RPC interface. When a pingback request is processed, WordPress first validates the URL against a whitelist of allowed domains and then proceeds to make an HTTP request to that URL. However, the race condition occurs because the validation occurs in one context while the actual HTTP request happens in another, allowing attackers to manipulate the target system between these two phases. This particular race condition enables attackers to bypass restrictions that should prevent access to internal network resources, including localhost addresses, private IP ranges, and other systems that are typically restricted from external access.
From an operational perspective, this vulnerability poses significant risks to WordPress installations as it allows attackers to perform reconnaissance and potentially exploit internal systems without authentication. The blind nature of the SSRF means that attackers cannot directly observe the responses from internal systems, but can still gather information through indirect methods such as timing attacks or by targeting systems that provide observable responses. The vulnerability particularly affects WordPress installations that are exposed to the internet and have not implemented proper network segmentation or firewall rules to protect internal services. This creates a potential attack vector where malicious actors could probe internal network infrastructure, potentially leading to further compromise of the WordPress installation or adjacent systems.
The impact of this vulnerability extends beyond simple information disclosure as it can serve as a stepping stone for more sophisticated attacks. Security researchers have noted that such blind SSRF vulnerabilities often provide attackers with the ability to perform internal network reconnaissance, which can reveal internal services, operating systems, and other sensitive information. The vulnerability is particularly concerning because it affects the core WordPress functionality and can be exploited without any authentication credentials, making it accessible to anyone who can submit pingback requests to a vulnerable WordPress installation. Organizations should consider implementing network-level protections, such as firewall rules that prevent outbound requests to internal IP ranges, and ensure that WordPress installations are properly updated to address this vulnerability.
This vulnerability aligns with CWE-1287 which specifically addresses blind server-side request forgery and demonstrates how race conditions in validation processes can create security weaknesses in web applications. The attack pattern follows typical SSRF techniques documented in the MITRE ATT&CK framework under the technique T1190 - Proxying, where attackers use legitimate system functionality to bypass security controls. The vulnerability also reflects broader concerns about XML-RPC interfaces in web applications, as the issue stems from how WordPress handles external requests through this interface. Organizations should implement proper input validation, maintain consistent state checking during request processing, and ensure that network access controls are in place to prevent unauthorized internal network access through application interfaces. The remediation involves updating WordPress installations to versions that address this specific race condition and implementing additional network-level controls to prevent unauthorized internal access patterns.