CVE-2025-20127

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SSL/TLS or VPN requests.\r\n\r\nThis vulnerability is due to the implementation of the TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. An attacker could exploit this vulnerability by sending a large number of TLS 1.3 connections with the specific TLS 1.3 Cipher TLS_CHACHA20_POLY1305_SHA256. A successful exploit could allow the attacker to cause a denial of service (DoS) condition where no new incoming encrypted connections are accepted. The device must be reloaded to clear this condition.\r\nNote: These incoming TLS 1.3 connections include both data traffic and user-management traffic. After the device is in the vulnerable state, no new encrypted connections can be accepted."}, {"lang": "es", "value": "Una vulnerabilidad en la implementaci\u00f3n de TLS 1.3 para un cifrado espec\u00edfico del software Cisco Secure Firewall Adaptive Security Appliance (ASA) y del software Cisco Secure Firewall Threat Defense (FTD) para dispositivos Cisco Firepower de las series 3100 y 4200 podr\u00eda permitir que un atacante remoto autenticado consuma recursos asociados con conexiones entrantes TLS 1.3, lo que eventualmente podr\u00eda provocar que el dispositivo deje de aceptar nuevas solicitudes SSL/TLS o VPN. Esta vulnerabilidad se debe a la implementaci\u00f3n del cifrado TLS_CHACHA20_POLY1305_SHA256 de TLS 1.3. Un atacante podr\u00eda explotar esta vulnerabilidad enviando un gran n\u00famero de conexiones TLS 1.3 con el cifrado TLS_CHACHA20_POLY1305_SHA256. Una explotaci\u00f3n exitosa podr\u00eda permitir al atacante causar una denegaci\u00f3n de servicio (DoS) donde no se aceptan nuevas conexiones cifradas entrantes. El dispositivo debe reiniciarse para solucionar esta situaci\u00f3n. Nota: Estas conexiones entrantes TLS 1.3 incluyen tanto tr\u00e1fico de datos como de administraci\u00f3n de usuarios. Una vez que el dispositivo se encuentra en estado vulnerable, no se pueden aceptar nuevas conexiones cifradas."}], "id": "CVE-2025-20127", "lastModified": "2026-08-11T19:33:44.513", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.7, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.1, "impactScore": 4.0, "source": "psirt@cisco.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-20127", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2025-08-14T18:41:43.684080Z", "version": "2.0.3"}}]}, "published": "2025-08-14T17:15:33.907", "references": [{"source": "psirt@cisco.com", "tags": ["Vendor Advisory"], "url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-3100_4200_tlsdos-2yNSCd54"}], "sourceIdentifier": "psirt@cisco.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-404"}], "source": "psirt@cisco.com", "type": "Secondary"}]}

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{"created": "2025-08-16T21:41:10.969028+00:00", "updated": "2025-08-16T21:41:10.969114+00:00", "vendors": ["cisco", "cisco$PRODUCT$adaptive_security_appliance_software", "cisco$PRODUCT$firepower_threat_defense_software"]}