CVE-2026-7839

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "modules": ["repeater"], "product": "UltraVNC", "vendor": "uvnc", "versions": [{"lessThanOrEqual": "1.8.2.2", "status": "affected", "version": "0", "versionType": "custom"}]}], "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:*", "matchCriteriaId": "593F7EC1-0922-4652-817A-7D57A0F1210D", "versionEndIncluding": "1.8.2.2", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "UltraVNC repeater through 1.8.2.2 initializes the HTTP administration server with a hardcoded default password. In repeater/webgui/settings.c:197, when settings2.txt is absent on first run the repeater writes the literal string \"adminadmi2\" as the admin password via strcpy_s(saved_password, 64, \"adminadmi2\"). The HTTP Basic-auth handler wi_decode_auth() checks this password without rate-limiting or lockout. Any remote attacker who can reach the repeater HTTP port (default TCP 80) can authenticate as administrator using the well-known default credential on a fresh or unmodified installation, gaining full control of the repeater configuration including allow/deny rules and session visibility."}, {"lang": "es", "value": "El repetidor UltraVNC hasta la versi\u00f3n 1.8.2.2 inicializa el servidor de administraci\u00f3n HTTP con una contrase\u00f1a predeterminada codificada de forma r\u00edgida. En repeater/webgui/settings.c:197, cuando settings2.txt est\u00e1 ausente en la primera ejecuci\u00f3n, el repetidor escribe la cadena literal \u2019adminadmi2\u2019 como la contrase\u00f1a de administrador a trav\u00e9s de strcpy_s(saved_password, 64, \u2019adminadmi2\u2019). El gestor de autenticaci\u00f3n b\u00e1sica HTTP wi_decode_auth() verifica esta contrase\u00f1a sin limitaci\u00f3n de velocidad ni bloqueo. Cualquier atacante remoto que pueda alcanzar el puerto HTTP del repetidor (TCP 80 predeterminado) puede autenticarse como administrador utilizando la credencial predeterminada bien conocida en una instalaci\u00f3n nueva o sin modificar, obteniendo control total de la configuraci\u00f3n del repetidor, incluyendo reglas de permitir/denegar y visibilidad de sesi\u00f3n."}], "id": "CVE-2026-7839", "lastModified": "2026-10-25T17:10:00.197", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-7839", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-07-01T12:32:28.823292Z", "version": "2.0.3"}}]}, "published": "2026-07-01T05:16:24.680", "references": [{"source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "tags": ["Product"], "url": "https://github.com/ultravnc/UltraVNC"}, {"source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "tags": ["Product", "Release Notes"], "url": "https://uvnc.com/"}, {"source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "url": "https://www.securin.io/zero-days/cve-2026-7839-hardcoded-default-admin-password-adminadmi2-ultravnc-repeater"}], "sourceIdentifier": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-798"}], "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c", "type": "Secondary"}]}

{}

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