CVE-2026-5229

Description

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. 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.

CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.34%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

References

Other References

https://github.com/oberonlai/form-notify/commit/5eab0ea https://github.com/oberonlai/form-notify/commit/9780764 https://plugins.trac.wordpress.org/browser/form-notify/tags/1.1.08/src/APIs/Line/Login/Route.php#L116-L118 https://plugins.trac.wordpress.org/browser/form-notify/tags/1.1.08/src/APIs/Line/Login/User.php#L53 https://plugins.trac.wordpress.org/browser/form-notify/tags/1.1.08/src/APIs/Line/Login/User.php#L72 https://plugins.trac.wordpress.org/browser/form-notify/trunk/src/APIs/Line/Login/Route.php#L116-L118 https://plugins.trac.wordpress.org/browser/form-notify/trunk/src/APIs/Line/Login/User.php#L53 https://plugins.trac.wordpress.org/browser/form-notify/trunk/src/APIs/Line/Login/User.php#L72 https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3517908%40form-notify&new=3517908%40form-notify&sfp_email=&sfph_mail= https://www.wordfence.com/threat-intel/vulnerabilities/id/2f0a7d6f-9b95-4052-bab3-85aca01f6ab7?source=cve

Frequently Asked Questions

What is CVE-2026-5229? +

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. 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. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-5229? +

CVE-2026-5229 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-5229? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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