4.4

CVE-2026-8981: unknown custom block builder Cross-site Scripting

CVSS: 4.4v3.1MediumDeferred
Published 09-06-2026Last modified 09-06-2026
Open JSON

Vulnerability summary

CVE-2026-8981 is a medium (CVSS 4.4) Cross-site Scripting vulnerability in unknown custom block builder. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.4% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 4.3.0.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
4.4/10
010
Medium · v3.1 (wordfence)
EPSS score
0.24%
0%100%
Low · +0.10 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Timeline

  1. 09-06-2026
    PublishedVulnerability first disclosed.
  2. 09-06-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

+0.10 pp

From 0.14% on 22-09-2026

22-09-202622-10-2026
EPSS score
0.24%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (wpscan.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Unknown1 product
Wordpress1 product
  • lazy-blocks< 4.3.0

2 vendors · 2 products

References

2 links