CVE-2026-63135
YOURLS is a self-hosted, customizable URL shortener written in PHP. From 1.5.1 until 1.10.4, YOURLS stores the HTTP Referer header through yourls_get_referrer(), yourls_sanitize_url_safe(), and yourls_log_redirect(), then aggregates the value in yourls-infos.php and passes the derived domain through yourls_get_domain(), yourls_stats_pie(), and yourls_google_array_to_data_table(). The chart builder concatenates labels into inline JavaScript without JavaScript-string escaping, so an unauthenticated attacker can poison the statistics of an existing short URL with a crafted referrer.
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When an administrator or public stats-page viewer opens the affected statistics page, attacker-controlled JavaScript executes in the YOURLS origin and can access admin-visible data, the API signature token, and privileged same-origin actions. This issue is fixed in version 1.10.4.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
- Puntuación base: 8.2
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.43%
- Percentil entre todas las CVEs puntuadas: 35
- 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
T1189Drive-by Compromiseinitial access95 % - Impacto principal
T1059.007JavaScriptexecution90 % - Impacto secundario
T1012Query Registrydiscovery75 %
XSS en referer HTTP almacenado sin escapar en JavaScript inline (CWE-79); ejecución de JS en el navegador del administrador al ver estadísticas, accediendo a tokens API y datos sensibles.
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://github.com/YOURLS/YOURLS/commit/e1e93476655107e6caab34e52259eb1c91079ec7
- https://github.com/YOURLS/YOURLS/pull/4107
- https://github.com/YOURLS/YOURLS/releases/tag/1.10.4
- https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659
- https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-63135",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-63135",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-08-26T17:40:19.146156Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 8.2,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "LOW"
},
"impactScore": 4.7,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "YOURLS",
"product": "YOURLS",
"versions": [
{
"status": "affected",
"version": ">= 1.5.1, < 1.10.4"
}
]
}
]
}
],
"published": "2026-08-21T21:17:01.493",
"references": [
{
"url": "https://github.com/YOURLS/YOURLS/commit/e1e93476655107e6caab34e52259eb1c91079ec7",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/YOURLS/YOURLS/pull/4107",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/YOURLS/YOURLS/releases/tag/1.10.4",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/YOURLS/YOURLS/security/advisories/GHSA-5h77-88j3-r659",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-79"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "YOURLS is a self-hosted, customizable URL shortener written in PHP. From 1.5.1 until 1.10.4, YOURLS stores the HTTP Referer header through yourls_get_referrer(), yourls_sanitize_url_safe(), and yourls_log_redirect(), then aggregates the value in yourls-infos.php and passes the derived domain through yourls_get_domain(), yourls_stats_pie(), and yourls_google_array_to_data_table(). The chart builder concatenates labels into inline JavaScript without JavaScript-string escaping, so an unauthenticated attacker can poison the statistics of an existing short URL with a crafted referrer. When an administrator or public stats-page viewer opens the affected statistics page, attacker-controlled JavaScript executes in the YOURLS origin and can access admin-visible data, the API signature token, and privileged same-origin actions. This issue is fixed in version 1.10.4."
}
],
"lastModified": "2026-09-09T21:06:39.057",
"sourceIdentifier": "security-advisories@github.com"
}