CVE-2026-3995

CVE-2026-3995 is a medium-severity vulnerability with a CVSS 3.x base score of 4.4. 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-79.

Key facts

Description

The OPEN-BRAIN plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'API Key' settings field in all versions up to, and including, 0.5.0. This is due to insufficient input sanitization and output escaping. The plugin uses sanitize_text_field() which strips HTML tags but does not encode double quotes or other HTML-special characters needed for safe attribute context output. The API key value is saved via update_option() and later output into an HTML input element's value attribute without esc_attr() escaping. This makes it possible for authenticated attackers, with Administrator-level access, to inject arbitrary web scripts via attribute breakout payloads (e.g., double quotes followed by event handlers) that execute whenever a user accesses the plugin settings page.

Frequently asked questions

What is CVE-2026-3995?
The OPEN-BRAIN plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'API Key' settings field in all versions up to, and including, 0.5.0. This is due to insufficient input sanitization and output escaping. The plugin uses sanitize_text_field() which strips HTML tags but does not encode double quotes or other HTML-special characters needed for safe attribute context output. The API key value is saved via update_option() and later output into an HTML input element's value attribute without esc_attr() escaping. This makes it possible for authenticated attackers, with Administrator-level access, to inject arbitrary web scripts via attribute breakout payloads (e.g., double quotes followed by event handlers) that execute whenever a user accesses the plugin settings page.
How severe is CVE-2026-3995?
CVE-2026-3995 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over network with high attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2026-3995 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-3995?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3995 have an EU (EUVD) identifier?
Yes. CVE-2026-3995 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23213.
When was CVE-2026-3995 published?
CVE-2026-3995 was published on 2026-04-16 and last updated on 2026-06-17.

References

Other CWE-79 (Cross-site Scripting (XSS)) vulnerabilities

Browse all CWE-79 (Cross-site Scripting (XSS)) vulnerabilities →