CVE-2026-86707 in Private Feed Key Plugin
Summary
by MITRE • 09/17/2026
The Private Feed Key WordPress plugin through 0.1 does not verify that the key used to authenticate a feed request is one it issued, matching any stored user metadata value instead, which allows unauthenticated attackers to log in as any user, including administrators.
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Analysis
by VulDB Data Team • 09/17/2026
The vulnerability identified within the Private Feed Key WordPress plugin prior to version 0.1 represents a critical authentication bypass flaw rooted in improper verification of cryptographic credentials. The core technical deficiency lies in the application's logic for validating feed access requests. Instead of maintaining a strict binding between the issued key and its specific originator or session context, the software performs a loose comparison against stored user metadata values. This architectural oversight means that any valid string present within the designated metadata field is accepted as an authentic token, regardless of whether it was generated by the plugin's own secure key generation mechanism. By failing to verify that the presented key matches one explicitly issued and tracked by the system during its creation phase, the application effectively nullifies the intended access control measures designed to restrict feed visibility to authorized subscribers only.
This flaw has severe operational implications for WordPress site administrators and their users. Because the authentication check is bypassed through this metadata matching mechanism, unauthenticated attackers can forge valid-looking requests that the server accepts as legitimate. This capability allows an attacker to impersonate any user account on the platform without possessing a password or completing standard login procedures. The severity of this impact is amplified by the potential for privilege escalation; since the vulnerability applies across all user roles, it enables low-privilege users or external attackers to log in as administrators. Once authenticated with administrative privileges, an attacker gains full control over the WordPress installation, including the ability to modify site settings, install malicious plugins, access sensitive database information, and potentially compromise other sites on a shared hosting environment if multi-site features are active.
From a classification perspective, this vulnerability aligns closely with CWE-287, which describes Improper Authentication, specifically falling under scenarios where an actor is able to bypass authentication mechanisms due to weak credential verification logic. Furthermore, the exploitation technique maps directly to MITRE ATT&CK tactic T1078, Valid Accounts, and more specifically sub-technique T1078.002, which covers Domain or Local Accounts obtained through phishing or other means of acquisition, although in this case, the accounts are accessed via forged credentials rather than stolen ones. The attack vector is typically classified as Network-based with Low complexity, allowing remote exploitation without prior access to the system.
To mitigate this vulnerability and prevent unauthorized access, immediate action must be taken by site administrators. The primary recommendation is to update the Private Feed Key plugin to version 0.1 or any subsequent release where the authentication logic has been corrected to strictly validate that keys are both issued by the application and correctly bound to their intended user context. If updating is not immediately feasible due to compatibility constraints, a temporary mitigation involves disabling the feed functionality entirely until an upgrade can be performed. Additionally, administrators should review server logs for signs of unauthorized access attempts or unusual feed consumption patterns indicative of exploitation. Implementing Web Application Firewall rules that monitor for anomalous authentication requests and enforcing strict input validation on all metadata fields used in security checks can also provide a layer of defense against similar logic flaws in other plugins.