CVE-2026-109320 in Grav API Plugin
Summary
by MITRE • 10/12/2026
The Grav API plugin (grav-plugin-api) before 1.0.36 contains an improper session validation vulnerability that allows disabled accounts to keep API access, because SessionAuthenticator does not enforce account state. Disabled users can reuse an already authorized browser or remember-me session to call API endpoints until expiry, defeating operator revocation.
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Analysis
by VulDB Data Team • 10/12/2026
The Grav CMS plugin known as grav-plugin-api contains a critical authentication bypass vulnerability in versions prior to 1.0.36 that undermines the fundamental security principle of account state enforcement during active sessions. This flaw stems from an improper session validation mechanism within the SessionAuthenticator component, which fails to verify whether the user associated with a given session token remains in an authorized or enabled state on the server side. Instead of checking the current status of the user account against the database for every API request, the plugin relies solely on the validity and expiration time of the existing session identifier. This architectural oversight creates a significant gap between administrative actions taken to revoke access and the actual enforcement of those revocations in active sessions.
From a technical perspective, the vulnerability allows disabled or deactivated accounts to retain full functionality within the application programming interface until their current browser or remember-me session expires naturally. When an administrator disables a user account, intending to immediately cut off that individual's ability to interact with the system, the backend does not invalidate existing active sessions associated with that identity. Consequently, any API calls made using a previously authenticated token remain valid and are processed successfully by the server. This behavior persists regardless of whether the session is short-lived or long-term, as the validation logic only checks for cryptographic integrity and timestamp expiration rather than current user privileges.
The operational impact of this vulnerability is substantial, particularly in environments where rapid response to security incidents or personnel changes is required. Attackers who have obtained credentials for a disabled account can continue to exploit API endpoints that may expose sensitive data, allow configuration modifications, or facilitate further lateral movement within the system. This defeats standard incident response procedures that rely on immediate account disabling as a containment measure. Furthermore, because the session remains active until its predefined expiry time, there is no mechanism for administrators to force an immediate logout of compromised accounts without manually clearing all server-side sessions or restarting services, which may not be feasible in production environments with high availability requirements.
This flaw aligns closely with Common Weakness Enumeration category CWE-613, which describes insufficient session expiration, and more specifically relates to CWE-287 regarding improper authentication checks that fail to verify current authorization status during active sessions. In the context of the MITRE ATT&CK framework, this vulnerability facilitates Initial Access persistence and can be leveraged for Defense Evasion by allowing attackers to maintain access through disabled accounts while evading detection mechanisms that monitor account state changes. The lack of real-time session invalidation means that security monitoring tools may not immediately flag continued activity from a logically disabled user as anomalous until the session naturally terminates or manual intervention occurs.
To mitigate this vulnerability, organizations must upgrade the grav-plugin-api to version 1.0.36 or later, where the SessionAuthenticator has been patched to enforce account state validation on every request. Until an update can be applied, administrators should implement compensating controls such as configuring shorter session lifetimes to reduce the window of opportunity for exploitation. Additionally, implementing a centralized authentication service that validates user status against a directory before processing API requests can provide an additional layer of security. It is also advisable to review access logs for any unusual activity from recently disabled accounts and manually invalidate active sessions if immediate containment is necessary. Regular auditing of session management practices and ensuring that all third-party plugins adhere to strict state validation protocols are essential steps in maintaining a robust security posture against similar authentication bypass flaws.