WordPress Core <= 7.1 - Forced Theme Install/Preview and Selector Injection via Theme Installer Route

2026-09-17 00:00

Strategic Overview

Status: Patched in 6.6.8
Affected Core: WordPress 7.1
Affected Version: 6.6.7 – 7.1 · 6 branches
CVSS: 4.3Medium
Weakness type: CWE-1021 · Improper Restriction of Rendered UI Layers or Frames
CVE: CVE pending

At a glance

This record tracks a medium-severity Improper Restriction of Rendered UI Layers or Frames vulnerability in the WordPress 7.1 WordPress release line, affecting 6.6.7 – 7.1 · 6 branches. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 6.6.8; sites on affected versions should update now. Disclosed September 2026, reported by Paulos Yibelo.

Vulnerability Overview

WordPress Core's theme installer (theme.js RunInstaller) passed the 'theme' slug from theme-install.php?theme=<slug> into a jQuery attribute selector ($('div[data-slug="'+slug+'"]')) without escaping, and matched any element rather than only theme cards. A crafted URL can automatically install and preview an inactive WordPress.org theme and inject an arbitrary jQuery selector.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-1021: Improper Restriction of Rendered UI Layers or Frames

The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain.

Remediation

Update to one of the following versions, or a newer patched version: 6.6.8, 6.7.8, 6.8.9, 6.9.8, 7.0.5, 7.1.1

How does WordSec protect against this?

The fix is the thing that ends this: updating to 6.6.8 is the step that ends it.

Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/c34ef5e3-afcd-4686-861f-5e382812233a

Related records

Same weakness class

7.1CVE-2011-3127: WordPress Core < 3.1.3 ClickjackingCVE-2011-3127

Other vulnerabilities in WordPress 7.1

CVSS Vector

4.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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