What is the CVSS score of CVE-2026-12399?

CVE-2026-12399 has a CVSS 3.1 base score of 4.4 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.2%.

Gutenverse CVE-2026-12399

EUVD-2026-39959 MEDIUM

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

2026-06-27 Wordfence

GHSA-pgr2-vvf9-xmqw

WordPress XSS Wordpress Plugin Gutenverse Wordpress Blocks Page Builder Site Editor Jegstudio

4.4

CVSS 3.1 · Vendor: Wordfence

Severity by source

Vendor (Wordfence) PRIMARY

4.4 MEDIUM

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

vuln.today AI

4.0 MEDIUM

Editor auth (PR:H) and deployment-specific conditions (AC:H) required; victim page visit needed (UI:R); scope changes to visitor browsers (S:C).

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

4.0 AV:N/AC:L/AT:P/PR:H/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Primary rating from Vendor (Wordfence).

CVSS VectorVendor: Wordfence

Attack Vector

Network

Attack Complexity

High

Privileges Required

High

User Interaction

None

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Lifecycle Timeline

Analysis Generated

Jun 27, 2026 - 07:53 vuln.today

CVE Published

Jun 27, 2026 - 06:50 cve.org

MEDIUM 4.4

DescriptionCVE.org

The Gutenverse - WordPress Blocks, Page Builder & Site Editor plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 3.8.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with editor-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

AnalysisAI

Stored Cross-Site Scripting in the Gutenverse WordPress Blocks, Page Builder & Site Editor plugin (all versions through 3.8.0) enables authenticated editor-level users to persist arbitrary JavaScript into pages served to any site visitor. The vulnerability is constrained to WordPress multi-site installations or single-site deployments where unfiltered_html has been explicitly disabled. No public exploit has been identified at time of analysis, and a upstream fix commit (changeset 3578328) has been published to the WordPress plugin repository.

Technical ContextAI

Gutenverse (CPE: cpe:2.3:a:jegstudio:gutenverse_-_wordpress_blocks,_page_builder_&_site_editor:*:*:*:*:*:*:*:*) is a Gutenberg-based WordPress page builder plugin. The root cause is CWE-79 (Improper Neutralization of Input During Web Page Generation), specifically insufficient input sanitization and output escaping in admin-facing settings handlers. Vulnerable code paths span at least five files identified via Wordfence and WordPress Trac references: helper.php (lines 1440 and 1775), class-api.php (line 1956), class-global-variable.php (line 78), and class-frontend-generator.php (line 147). These files collectively handle global variable registration, API endpoint processing, and frontend page generation - meaning attacker-controlled data flows from settings input through storage and is later reflected to page visitors without adequate escaping. WordPress normally prevents editors from injecting unfiltered HTML via the unfiltered_html capability, but this plugin bypasses that protection through its own settings pipeline.

RemediationAI

Upstream fix commit (changeset 3578328 at https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3578328%40gutenverse&new=3578328%40gutenverse) has been published to the WordPress plugin repository; update Gutenverse to the version incorporating this changeset as soon as it is tagged and available via the WordPress plugin updater. The exact released patched version number is not independently confirmed from available data - verify via the plugin changelog before updating. As a compensating control where immediate patching is not possible: restrict editor-level role assignment to fully trusted accounts, as this is the minimum privilege required for exploitation. On multi-site networks, consider auditing network admin settings for unexpected changes. Sites where unfiltered_html is disabled as a deliberate hardening measure should treat this as a higher-priority update since that configuration is precisely the one that enables the attack path; re-enabling unfiltered_html as a workaround would eliminate the vulnerability condition but reintroduce broader HTML injection risk and is not recommended.