CVE-2026-13400

mediumCVSS 6.1covered by 1 sourcefirst seen 2026-07-27

Simply Schedule Appointments is vulnerable to unauthenticated Stored Cross-Site Scripting in all versions up to and including 1.6.12.2. The root cause is a sanitization-ordering defect: the rendered notification content is decoded back into live HTML after it has already passed through the Simply Schedule Appointments WordPress plugin before 1.6.12.4's wp_kses_post() filter, so a double-encoded payload survives intake and is reintroduced as an executable element at render time.

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Exploitation outlook

Low exploitation risk0.15% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 5% of all EPSS-scored CVEs.

Advisory coverage (1)

mediumCVE-2026-13400: Simply Schedule Appointments is vulnerable to unauthenticated Stored Cross-Site Scripting in a…nvd · 2026-07-27

External references

NVD record for CVE-2026-13400

CVE.org record

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