CVE-2026-3552 in SurfLink Plugin
Summary
by MITRE • 07/11/2026
The SurfLink - Ultimate Link Manager plugin for WordPress is vulnerable to unauthorized data modification due to a missing capability check on the ajax_import_410() function in all versions up to 2.6.0. This is due to a missing capability check (current_user_can()) and missing nonce verification (check_ajax_referer()) in the ajax_import_410() function, while all other AJAX handlers in the same class (ajax_add_single_410, ajax_save_editted_410, ajax_delete_410, ajax_bulk_410_delete, ajax_empty_410, ajax_export_410) properly implement both authorization and nonce checks. This makes it possible for authenticated attackers, with Subscriber-level access and above, to import arbitrary URLs into the 410 Gone database table via the surfl_import_410 AJAX action. Injected URLs will cause the site to return HTTP 410 Gone responses to all visitors accessing those paths, potentially causing denial of service for legitimate pages and SEO damage through search engine delisting.
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Analysis
by VulDB Data Team • 07/11/2026
The SurfLink - Ultimate Link Manager plugin for WordPress presents a critical security vulnerability that allows unauthorized data modification through insufficient access controls within its AJAX handling mechanisms. This vulnerability specifically affects all versions up to 2.6.0 and stems from a fundamental flaw in the ajax_import_410() function which lacks proper capability verification and nonce validation. The issue manifests as a missing current_user_can() check that should validate whether the authenticated user possesses sufficient privileges to perform data modification operations, combined with an absence of check_ajax_referer() function that would verify the authenticity of AJAX requests through nonce verification.
The technical implementation flaw represents a clear deviation from secure coding practices and constitutes a CWE-863 vulnerability categorized as "Incorrect Authorization" where the application fails to properly verify that an actor has adequate access rights to perform a requested operation. This weakness exists alongside other functions within the same class that correctly implement both authorization and nonce verification, creating an inconsistent security posture within the plugin's codebase. The ajax_import_410() function operates with elevated privileges while other similarly named functions maintain proper security controls, demonstrating a pattern of incomplete security implementation rather than a systemic architectural failure.
The operational impact of this vulnerability extends beyond simple data modification to encompass significant service disruption and potential reputational damage for affected websites. Authenticated attackers with Subscriber-level access or higher can exploit this weakness to inject arbitrary URLs into the 410 Gone database table, effectively transforming legitimate website paths into HTTP 410 Gone responses that return error codes to all visitors accessing those specific URLs. This capability enables attackers to perform targeted denial of service attacks against critical website sections while simultaneously causing SEO degradation through search engine delisting of affected pages.
The security implications align with ATT&CK technique T1213.002 "Data from Information Repositories" and T1499.004 "Network Denial of Service" where adversaries can manipulate repository data to cause service disruption. The vulnerability creates a persistent threat vector that allows attackers to maintain control over website content delivery by modifying the 410 Gone database, potentially affecting multiple website sections simultaneously. This modification capability also enables attackers to redirect traffic patterns and create artificial service disruptions while maintaining plausible deniability since the modifications appear to originate from legitimate user activity.
Mitigation strategies should focus on immediate remediation through plugin updates to versions that properly implement authorization and nonce verification for all AJAX handlers. System administrators must ensure that all WordPress plugins maintain consistent security practices across their entire codebase, particularly in AJAX handling functions where privilege escalation risks are highest. The implementation of proper capability checks using current_user_can() combined with nonce verification through check_ajax_referer() creates a robust defense-in-depth approach that aligns with OWASP Top Ten 2021 category A07:2021 - Identification and Authentication Failures. Additionally, implementing request rate limiting and monitoring for unusual AJAX activity patterns can provide additional detection capabilities for potential exploitation attempts.