CVE-2026-77820
The WPComplete plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'empty' Shortcode Attribute in all versions up to, and including, 2.9.9.0 due to insufficient input sanitization and output escaping. 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 an injected page. This requires the premium version of the software in order to exploit. Please note this only affects the pro version.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Puntuación base: 6.4
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.33%
- Percentil entre todas las CVEs puntuadas: 24
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1190Exploit Public-Facing Applicationinitial access85 % - Impacto principal
T1059.007JavaScriptexecution80 %
Plugin WordPress vulnerable a XSS almacenado (CWE-79) con autenticación de contributor. AV:N/PR:L permite inyección web que ejecuta scripts en navegadores de usuarios accediendo a páginas comprometidas.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-79
Referencias
- https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/includes/class-wpcomplete.php#L305
- https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1692
- https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1802
- https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1859
- https://www.wordfence.com/threat-intel/vulnerabilities/id/5b91bb81-b5e4-4a50-833b-e2e98ccc09ff?source=cve
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-77820",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-77820",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-19T13:22:18.614551Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security@wordfence.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 6.4,
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
"integrityImpact": "LOW",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "LOW",
"confidentialityImpact": "LOW"
},
"impactScore": 2.7,
"exploitabilityScore": 3.1
}
]
},
"affected": [
{
"source": "security@wordfence.com",
"affectedData": [
{
"vendor": "stellarwp",
"product": "WPComplete",
"versions": [
{
"status": "affected",
"version": "0",
"versionType": "semver",
"lessThanOrEqual": "2.9.9.0"
}
],
"defaultStatus": "unaffected"
}
]
}
],
"published": "2026-09-19T02:16:54.257",
"references": [
{
"url": "https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/includes/class-wpcomplete.php#L305",
"source": "security@wordfence.com"
},
{
"url": "https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1692",
"source": "security@wordfence.com"
},
{
"url": "https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1802",
"source": "security@wordfence.com"
},
{
"url": "https://plugins.trac.wordpress.org/browser/wpcomplete/tags/2.9.5.7/public/class-wpcomplete-public.php#L1859",
"source": "security@wordfence.com"
},
{
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/5b91bb81-b5e4-4a50-833b-e2e98ccc09ff?source=cve",
"source": "security@wordfence.com"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security@wordfence.com",
"description": [
{
"lang": "en",
"value": "CWE-79"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "The WPComplete plugin for WordPress is vulnerable to Stored Cross-Site Scripting via 'empty' Shortcode Attribute in all versions up to, and including, 2.9.9.0 due to insufficient input sanitization and output escaping. 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 an injected page. This requires the premium version of the software in order to exploit. Please note this only affects the pro version."
}
],
"lastModified": "2026-09-21T13:33:33.387",
"sourceIdentifier": "security@wordfence.com"
}