CVE-2026-5229

CVE-2026-5229 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

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.

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.
How severe is CVE-2026-5229?
CVE-2026-5229 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-5229 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-5229?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-5229 have an EU (EUVD) identifier?
Yes. CVE-2026-5229 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30516.
When was CVE-2026-5229 published?
CVE-2026-5229 was published on 2026-05-15 and last updated on 2026-06-17.

References

Other CWE-287 (Improper Authentication) vulnerabilities

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