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Vulnerabilities

Vulnerability · CVE-2026-4279

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 incl…

Published Apr 22, 2026 · catalog updated Jun 17, 2026 · the affected product

Check if you run it

No confirmed exploitation is on record for CVE-2026-4279. EPSS is 0.33%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium6.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.33%
Remediation
Version ranges on file
Affected products
stated named in the record

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • stated named in the record<= 8.2.0

How to fix CVE-2026-4279

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4279. EPSS is 0.33%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with named in the record <= 8.2.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 22, 2026 · NIST NVD

    Detected

    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 J

  2. Jun 17, 2026 · NIST NVD

    Updated

    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 J

Sources

  • CVE.orgVulnerability recordCVE-2026-4279

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4279

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-4279

    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 attr

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.