CVE-2026-8981

Lazy Blocks < 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML

Low · published June 9, 2026

CVSS v3.1
3.5
EPSS
0%
Percentile
14.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
3.5 · LOW
Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00242 · 14.5th percentile
Published
2026-06-09T06:00Z
EPSS history
Timeline
  • 09 JUN 06:00Z
    Lazy Blocks < 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML
    cvelistv5