CVE-2026-104000

HIGHCVSS 7.2/10EPSS 0.24%

Last modified

CVE-2026-104000 is a high-severity vulnerability rated 7.2/10 on the CVSS scale. The Simply Schedule Appointments plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'status' parameter in all versions up to, and including, 1.6.12.35 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. EPSS estimates a 0.24% chance of exploitation in the next 30 days.

Description

The Simply Schedule Appointments plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'status' parameter in all versions up to, and including, 1.6.12.35 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The malicious payload is stored unconditionally because debug logging is enabled by default, and the debug-log viewer is accessible to anyone holding the site-wide Support PIN (an HMAC-MD5 of AUTH_SALT displayed in wp-admin), meaning the injected script will execute against the administrator's session during ordinary support or troubleshooting workflows.

Metrics

EPSS Probability
0.24%

13.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
croixhaugSimply Schedule Appointments<= 1.6.12.35

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-104000?
The Simply Schedule Appointments plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'status' parameter in all versions up to, and including, 1.6.12.35 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The malicious payload is stored unconditionally because debug logging is enabled by default, and the debug-log viewer is accessible to anyone holding the site-wide Support PIN (an HMAC-MD5 of AUTH_SALT displayed in wp-admin), meaning the injected script will execute against the administrator's session during ordinary support or troubleshooting workflows.
How severe is CVE-2026-104000?
CVE-2026-104000 has a CVSS score of 7.2/10 (HIGH severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.
How do I fix CVE-2026-104000?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST