CVE-2026-100667

Deferred Deferred - Pending Action

Two-Factor Authentication Bypass in Grav CMS Login Plugin

Publication date: 2026-09-26

Last updated on: 2026-09-28

Assigner: VulnCheck

Description

grav-plugin-login (the Grav CMS Login plugin) versions >= 3.8.7 and < 3.9.7 allow the two-factor authentication challenge to be bypassed for content gated by the authenticated() Twig function or the [authenticated] shortcode. On sites with 2FA enabled, Login::isAuthenticated() checked only the session flag indicating that the password step had succeeded, not the flag indicating that login had completed, so a session sitting at the 2FA code prompt was treated as fully authenticated. An attacker who knows a member's password but cannot answer that member's second factor can therefore read member-only content rendered by the no-argument authenticated() or group authenticated(null, 'group') forms and by [authenticated]; the inverse [guest] shortcode is likewise evaluated too early. Impact is limited to disclosure of that content: the attacker does not obtain a completed session, cannot access pages protected by an access: rule, and cannot act as the user. The authenticated('some.permission') form, which goes through UserObject::authorize(), is not affected. Fixed in grav-plugin-login 3.9.7.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-26

Last Modified

2026-09-28

Generated

2026-10-17

AI Q&A

2026-09-26

EPSS Evaluated

2026-10-14

NVD

CVE-2026-100667

EUVD

EUVD-2026-87761

Affected Vendors & Products

Vendor	Product	Version / Range
grav	grav-plugin-login	to 3.9.7 (inc)
getgrav	grav-plugin-login	From 3.8.7 (inc) to 3.9.7 (exc)
getgrav	grav-plugin-login	3.9.7

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-304	The product implements an authentication technique, but it skips a step that weakens the technique.

Attack-Flow Graph

Executive Summary

The vulnerability in grav-plugin-login versions 3.8.7 to 3.9.6 allows bypassing two-factor authentication (2FA) for Grav CMS. The plugin incorrectly checks only if the password step was completed, not the full 2FA process. This lets an attacker with a user's password but no access to their 2FA method view member-only content protected by the authenticated() function or [authenticated] shortcode.

Detection Guidance

Check the installed version of grav-plugin-login. If it is between 3.8.7 and 3.9.6, the system is vulnerable. Use commands like 'composer show grav-plugin-login' or check the plugin directory in Grav CMS.

Impact Analysis

An attacker who knows a user's password but cannot bypass 2FA can access restricted content. The impact is limited to content disclosure; they cannot gain full session access, bypass stricter access rules, or perform actions as the user.

Compliance Impact

This vulnerability could potentially affect compliance with GDPR and HIPAA by allowing unauthorized access to member-only content. GDPR requires protection of personal data, and HIPAA mandates safeguards for protected health information. The flaw enables attackers with a user's password but no access to their second factor to view restricted content, which may include sensitive personal or health data. This unauthorized disclosure could violate confidentiality requirements under these regulations.

Mitigation Strategies

Upgrade grav-plugin-login to version 3.9.7 or later immediately.
Replace affected [authenticated] shortcodes with page-level access rules as a temporary workaround.
Review and restrict access to member-only content until the plugin is updated.

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