CVE-2026-81889
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Prior to 2.1.70, elFinder URL uploads in php/elFinder.class.php can bypass server-side request forgery protections when PHP cURL is unavailable because validate_address() validates $info['ip'], but get_remote_contents() selects fsock_get_contents(), which connects to $arr['host'] and performs a second DNS resolution.
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An attacker able to submit a URL upload can use DNS rebinding to have the first resolution return a public address and the connection resolution return a loopback or private address, causing the internal HTTP response body to be stored as an uploaded file and made readable through elFinder. After a successful fetch, get_headers($url, true) separately requests the original hostname without reusing the validated and pinned connection, creating an additional blind server-side request forgery path even when curl_get_contents() is selected. This issue is fixed in version 2.1.70.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
- Puntuación base: 8.6
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.55%
- Percentil entre todas las CVEs puntuadas: 44
- Fecha de la puntuación: 5/10/2026
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 access90 % - Impacto principal
T1090Proxycommand and control85 % - Impacto secundario
T1005Data from Local Systemcollection80 %
AV:N, PR:N, UI:N → red sin privilegios. DNS rebinding (T1090) y lectura de respuestas HTTP internas (T1005) tras bypasear SSRF mediante resolución dual de DNS.
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-918
Referencias
- https://github.com/Studio-42/elFinder/commit/191372c1bbebbd36fb55af79a84b9984861390ff
- https://github.com/Studio-42/elFinder/commit/6d997386cd0f1abab4706c220b46b0aea0ecff51
- https://github.com/Studio-42/elFinder/releases/tag/2.1.70
- https://github.com/Studio-42/elFinder/security/advisories/GHSA-8x3q-jpjh-qh5c
- https://github.com/Studio-42/elFinder/security/advisories/GHSA-8x3q-jpjh-qh5c
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-81889",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-81889",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-03T18:04:00.867870Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 8.6,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 4,
"exploitabilityScore": 3.9
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "Studio-42",
"product": "elFinder",
"versions": [
{
"status": "affected",
"version": "< 2.1.70"
}
]
}
]
}
],
"published": "2026-08-31T21:17:52.460",
"references": [
{
"url": "https://github.com/Studio-42/elFinder/commit/191372c1bbebbd36fb55af79a84b9984861390ff",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Studio-42/elFinder/commit/6d997386cd0f1abab4706c220b46b0aea0ecff51",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Studio-42/elFinder/releases/tag/2.1.70",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Studio-42/elFinder/security/advisories/GHSA-8x3q-jpjh-qh5c",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Studio-42/elFinder/security/advisories/GHSA-8x3q-jpjh-qh5c",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-918"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Prior to 2.1.70, elFinder URL uploads in php/elFinder.class.php can bypass server-side request forgery protections when PHP cURL is unavailable because validate_address() validates $info['ip'], but get_remote_contents() selects fsock_get_contents(), which connects to $arr['host'] and performs a second DNS resolution. An attacker able to submit a URL upload can use DNS rebinding to have the first resolution return a public address and the connection resolution return a loopback or private address, causing the internal HTTP response body to be stored as an uploaded file and made readable through elFinder. After a successful fetch, get_headers($url, true) separately requests the original hostname without reusing the validated and pinned connection, creating an additional blind server-side request forgery path even when curl_get_contents() is selected. This issue is fixed in version 2.1.70."
}
],
"lastModified": "2026-09-09T21:09:13.080",
"sourceIdentifier": "security-advisories@github.com"
}