CVE-2026-4091

CVE-2026-4091 is a medium-severity vulnerability with a CVSS 3.x base score of 6.1. 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-352.

Key facts

Description

The OPEN-BRAIN plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.5.0. This is due to missing nonce verification on the settings form in the func_page_main() function. This makes it possible for unauthenticated attackers to inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Frequently asked questions

What is CVE-2026-4091?
The OPEN-BRAIN plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 0.5.0. This is due to missing nonce verification on the settings form in the func_page_main() function. This makes it possible for unauthenticated attackers to inject malicious web scripts via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.
How severe is CVE-2026-4091?
CVE-2026-4091 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-4091 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-4091?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-4091 have an EU (EUVD) identifier?
Yes. CVE-2026-4091 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-22870.
When was CVE-2026-4091 published?
CVE-2026-4091 was published on 2026-04-15 and last updated on 2026-06-17.

References

Other CWE-352 (Cross-Site Request Forgery (CSRF)) vulnerabilities

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