CVE-2026-4279 json
Bread & Butter: Content Gating for Verified Leads <= 8.2.0.25 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
published 2026-04-22 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-24686
- cvss
- 6.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 14%
- public exploits
- 0
- none known
Summary
The Bread & Butter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'breadbutter-customevent-button' shortcode in all versions up to, and including, 8.2.0.25. This is due to insufficient input sanitization and output escaping on the 'event' shortcode attribute. The customEventShortCodeButton() function takes the 'event' attribute value and directly interpolates it into a JavaScript string within an onclick HTML attribute without applying esc_attr() or esc_js(). Notably, the sister function customEventShortCode() properly uses esc_js() for the same attribute, but this was omitted in the button variant. 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 the page and clicks the injected button.
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 6 mo ago
Exploit prediction
0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
Affected products
- breadbutter Bread & Butter: AI-Powered Lead Intelligence
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
- Technology feeds
References
- wordfence.com /threat-intel/vulnerabilities/id/0728b42b-5ec7-46a2-a9a5-3316107e9324?source=cve
- plugins.trac.wordpress.org /browser/bread-butter/trunk/src/Base/Shortcode.php#L380
- plugins.trac.wordpress.org /browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L380
- plugins.trac.wordpress.org /browser/bread-butter/trunk/src/Base/Shortcode.php#L364
- plugins.trac.wordpress.org /browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L364
Sources
- CVE List CVE-2026-4279
- NVD CVE-2026-4279
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.