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Low 3.5Published Jun 9, 2026

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

Updated under an hour ago ()

Does this affect you?

It affects Unknown Custom Block Builder. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
3.5 LOW (v3.1, CISA ADP)CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-79
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
WPScan
NVD analysis
Deferred
Record last updated
Jun 9, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Unknown Custom Block Builder
unknown:custom_block_builder (from the name)
before 4.3.0
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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