Vulnerability · Published Jun 9, 2026 · Assigned by WPScan

CVE-2026-8981Lazy Blocks < 4.3.0 - Admin+ Stored XSS via Custom Block Frontend HTML

Low 3.5

In plain English

A low-severity cross-site scripting in Custom Block Builder from Unknown. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 3% of all known vulnerabilities).

Severity (CVSS 3.1)3.5Low

Exploit odds (30 days)0.1%top 96.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Unknown	Custom Block Builder	0 – before 4.3.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N

References

https://wpscan.com/vulnerability/9815b0e6-e411-4a5c-9c63-30bad21da698/ exploit, vdb-entry, technical-description