CVE-2026-109319 in Guestbook Plugin
Summary
by MITRE • 10/12/2026
Grav Guestbook plugin 0.5.0 and 0.5.1 contains missing authorization and cross-site request forgery vulnerabilities in Admin moderation actions delete, approve, and approveAll. Authenticated Admin users lacking the admin.guestbook permission, or external sites abusing a moderator's session via nonce-less GET requests, can delete or approve Guestbook entries.
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Analysis
by VulDB Data Team • 10/12/2026
The Grav Guestbook plugin versions 0.5.0 and 0.5.1 are affected by critical security flaws related to access control and request integrity. These vulnerabilities stem from insufficient authorization checks on administrative moderation endpoints and a lack of protection against cross-site request forgery attacks. The core issue lies in the implementation of actions such as deleting, approving, or bulk-approving guestbook entries, which fail to properly validate whether the requesting user possesses the necessary permissions or if the request originates from a trusted source without tampering.
From an access control perspective, the vulnerability allows authenticated administrative users who do not hold the specific admin.guestbook permission to execute moderation actions. This represents a classic case of broken object level authorization where the system fails to enforce role-based access controls correctly at the function level. An attacker with any valid administrator account that lacks this explicit permission can still manipulate guestbook data, bypassing intended security boundaries. This flaw aligns closely with CWE-269 Improper Privilege Management and CWE-862 Missing Authorization in industry standard classifications.
Furthermore, the plugin is susceptible to cross-site request forgery due to its reliance on nonce-less GET requests for these sensitive operations. By using simple HTTP GET methods without anti-CSRF tokens or other verification mechanisms, the application becomes vulnerable to malicious sites tricking an authenticated moderator into performing unintended actions. When a user visits a crafted webpage while logged into their Grav administration panel, the browser automatically includes session cookies with any outgoing request. Consequently, the server processes these forged requests as legitimate administrative commands. This weakness corresponds directly to CWE-352 Cross-Site Request Forgery and is often associated with ATT&CK technique T1078 Valid Accounts when combined with credential theft or persistence mechanisms.
The operational impact of these vulnerabilities allows for significant disruption to website integrity and content management workflows. An attacker can delete legitimate user comments, causing data loss and potential reputational damage to the site owner. Alternatively, they can approve spammy or malicious entries, which degrades the quality of community interaction and may facilitate further attacks through injected links or scripts within approved posts. In severe cases, this could lead to defacement if combined with other vulnerabilities in the broader Grav ecosystem.
To mitigate these risks, immediate updates to a patched version of the Grav Guestbook plugin are required as soon as they become available from the official repository. Until an update is deployed, administrators should consider restricting access to the administration area using IP whitelisting or multi-factor authentication to reduce exposure. Additionally, implementing server-side validation for all administrative actions and ensuring that state-changing operations use POST requests with valid anti-CSRF tokens can help mitigate forgery attempts. Regular audits of user permissions within the Grav platform are also recommended to ensure strict adherence to least privilege principles across all installed plugins.