FKIE_CVE-2026-4279

Vulnerability from fkie_nvd - Published: 2026-04-22 09:16 - Updated: 2026-04-22 20:22
Severity ?
6.4 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
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.
References
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L364
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L380
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/bread-butter/trunk/src/Base/Shortcode.php#L364
security@wordfence.comhttps://plugins.trac.wordpress.org/browser/bread-butter/trunk/src/Base/Shortcode.php#L380
security@wordfence.comhttps://www.wordfence.com/threat-intel/vulnerabilities/id/0728b42b-5ec7-46a2-a9a5-3316107e9324?source=cve
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The Bread \u0026 Butter plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the \u0027breadbutter-customevent-button\u0027 shortcode in all versions up to, and including, 8.2.0.25. This is due to insufficient input sanitization and output escaping on the \u0027event\u0027 shortcode attribute. The customEventShortCodeButton() function takes the \u0027event\u0027 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."
    }
  ],
  "id": "CVE-2026-4279",
  "lastModified": "2026-04-22T20:22:50.570",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.4,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 2.7,
        "source": "security@wordfence.com",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-04-22T09:16:25.160",
  "references": [
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L364"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/bread-butter/tags/8.2.0.25/src/Base/Shortcode.php#L380"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/bread-butter/trunk/src/Base/Shortcode.php#L364"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://plugins.trac.wordpress.org/browser/bread-butter/trunk/src/Base/Shortcode.php#L380"
    },
    {
      "source": "security@wordfence.com",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/0728b42b-5ec7-46a2-a9a5-3316107e9324?source=cve"
    }
  ],
  "sourceIdentifier": "security@wordfence.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security@wordfence.com",
      "type": "Primary"
    }
  ]
}


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