CVE-2026-5229
Published: 15 May 2026
Summary
CVE-2026-5229 is a critical-severity Improper Authentication (CWE-287) vulnerability in Wordpress (inferred from references). Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 49.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-30516
Vulnerability details
The Form Notify plugin for WordPress is vulnerable to Authentication Bypass in versions up to and including 1.1.10. This is due to the plugin trusting user-controlled cookie data to determine which WordPress account to authenticate after a LINE OAuth login.…
more
When LINE doesn't provide an email address (which is common), the plugin falls back to reading the 'form_notify_line_email' cookie value without verifying that the LINE account is associated with that email address. This makes it possible for unauthenticated attackers to gain access to any user account on the site, including administrator accounts, by completing a LINE OAuth flow with their own LINE account while injecting a malicious cookie containing the target victim's email address.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Auth bypass in public-facing WordPress plugin directly enables use of valid accounts (T1078) via exploitation of web application (T1190).
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Detects unauthorized successful logons resulting from improper authentication implementations.
Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.
Security awareness training instructs users on secure authentication practices and avoiding credential compromise.
Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.
Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.
Session content review can reveal authentication bypasses or failures in session establishment.
Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.
Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.