CVE-2026-6378Network attack vector

Author-level stored XSS via unsanitized style data

Published May 2, 2026 · Updated May 2, 2026

Stored XSS in MaxiBlocks Builder 2.1.9 and earlier allows remote authenticated users to inject scripts through the Style Card REST API. The post_maxi_blocks_sc_string method stores sc_styles without stripping tags, and enqueue_styles passes the value to wp_add_inline_style. Author-level access is required; injected scripts run wherever style-card styles load, including throughout the WordPress administration panel.

CVSS severity6.4
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in MaxiBlocks Builder 2.1.9 and earlier allows remote authenticated users to inject scripts through the Style Card REST API. The post_maxi_blocks_sc_string method stores sc_styles without stripping tags, and enqueue_styles passes the value to wp_add_inline_style. Author-level access is required; injected scripts run wherever style-card styles load, including throughout the WordPress administration panel.

The record

CVE
CVE-2026-6378
Published
May 2, 2026
Updated
May 2, 2026
Vendor
Christiaan Pieterse
Product
MaxiBlocks Builder
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 2, 2026CVE publishedPublication date reported by the CVE source.
  2. May 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.1.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Christiaan Pieterse · MaxiBlocks Builderversion=0 <=2.1.9

Published CVSS scores

6.4WordfenceCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript/JScript

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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