CVE-2026-8981
Lazy Blocks < 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML
Description
The Custom Block Builder WordPress plugin before 4.3.0 does not consistently check the unfiltered_html capability across all paths that write to its block template code fields, allowing administrators on multisite installations (or single-site installs with DISALLOW_UNFILTERED_HTML defined) to inject arbitrary JavaScript that executes for any visitor of pages embedding the affected block.
INFO
Published Date :
June 9, 2026, 6:16 a.m.
Last Modified :
July 23, 2026, 8:10 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the plugin to version 4.3.0 or later.
- Verify administrator capabilities and permissions.
- Review audit logs for suspicious activity.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-8981.
| URL | Resource |
|---|---|
| https://wpscan.com/vulnerability/9815b0e6-e411-4a5c-9c63-30bad21da698/ |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-8981 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-8981
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-8981 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-8981 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Jul. 23, 2026
Action Type Old Value New Value Added Translation Title: plugin de WordPress Custom Block Builder, Description: El plugin de WordPress Custom Block Builder anterior a la versión 4.3.0 no verifica de forma consistente la capacidad unfiltered_html en todas las rutas que escriben en sus campos de código de plantilla de bloque, permitiendo a los administradores en instalaciones multisitio (o instalaciones de sitio único con DISALLOW_UNFILTERED_HTML definido) inyectar JavaScript arbitrario que se ejecuta para cualquier visitante de las páginas que incrustan el bloque afectado. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Unknown', 'product': 'Custom Block Builder', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '4.3.0', 'versionType': 'semver'}], 'defaultStatus': 'unaffected'}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-8981', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-09T10:32:46.274624Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 09, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N Added CWE CWE-79 -
New CVE Received by [email protected]
Jun. 09, 2026
Action Type Old Value New Value Added Description The Custom Block Builder WordPress plugin before 4.3.0 does not consistently check the unfiltered_html capability across all paths that write to its block template code fields, allowing administrators on multisite installations (or single-site installs with DISALLOW_UNFILTERED_HTML defined) to inject arbitrary JavaScript that executes for any visitor of pages embedding the affected block. Added Reference https://wpscan.com/vulnerability/9815b0e6-e411-4a5c-9c63-30bad21da698/