Stored cross-site scripting in Stackable WordPress plugin
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
The Stackable Page Builder Gutenberg Blocks plugin for WordPress is affected in all versions up to and including 3.19.9. Missing input sanitization and output escaping in the update_block_style endpoint (CWE-79) lets an authenticated attacker with Contributor-level access or above store arbitrary web scripts. The scripts run in a user's browser whenever that user opens an injected page.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Description from the CNA
The Stackable – Page Builder Gutenberg Blocks plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'update_block_style' endpoint in all versions up to, and including, 3.19.9 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for Stackable Page Builder Gutenberg Blocks.
Written with Claude Haiku 5.5 from the sources below · 2026-11-07
Timeline
- 2026-11-07 Threatist record created from CVE-2026-9601
- 2026-11-07 Alias added: GHSA-7888-mmrq-c53f
- 2026-11-07 CISA SSVC decision points changed
- 2026-11-07 Priority changed: MEDIUM → LOW
References
Other 11
- https://www.wordfence.com/threat-intel/vulnerabilities/id/1d4da874-23c8-4df4-b776-6046ce8d705a?source=cve
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.6/src/deprecated/block-defaults/custom-block-styles.php#L223
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.8/src/deprecated/block-defaults/custom-block-styles.php#L223
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.8/src/deprecated/block-defaults/custom-block-styles.php#L181
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.8/src/deprecated/block-defaults/custom-block-styles.php#L155
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.8/src/deprecated/block-defaults/custom-block-styles.php#L432
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.6/src/deprecated/block-defaults/custom-block-styles.php#L181
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.6/src/deprecated/block-defaults/custom-block-styles.php#L155
- https://plugins.trac.wordpress.org/browser/stackable-ultimate-gutenberg-blocks/tags/3.19.6/src/deprecated/block-defaults/custom-block-styles.php#L432
- https://github.com/gambitph/Stackable/pull/3725
- https://plugins.trac.wordpress.org/changeset/3609541/stackable-ultimate-gutenberg-blocks/trunk/src/deprecated/block-defaults/custom-block-styles.php
More bfintal vulnerabilities
- TI-2024-05843 Stackable – Page Builder Gutenberg Blocks <= 3.13.1 - Authenticated (Contributor+) DOM-Based Stored Cross-Site Scripting CVSS 3.1MEDIUM 6.4
- TI-2024-01897 Cross-site scripting in bfintal Stackable – Page Builder Gutenberg Blocks CVSS 3.1MEDIUM 6.4
- TI-2025-11651 Cross-site scripting in bfintal Interactions – Create Interactive Experiences in the… CVSS 3.1MEDIUM 6.4
- TI-2022-04562 Freemius SDK <= 2.4.2 - Missing Authorization Checks CVSS 3.1MEDIUM 6.3
- TI-2024-08126 Stackable – Page Builder Gutenberg Blocks <= 3.13.6 - Unauthenticated CSS Injection CVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-9601 · CVE Program
- CVE-2026-9601 · NVD
- FIRST EPSS
- GHSA-7888-mmrq-c53f · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences