{"api_version":"1","generated_at":"2026-04-23T15:30:09+00:00","cve":"CVE-2021-1534","urls":{"html":"https://cve.report/CVE-2021-1534","api":"https://cve.report/api/cve/CVE-2021-1534.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-1534","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-1534"},"summary":{"title":"CVE-2021-1534","description":"A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.","state":"PUBLIC","assigner":"psirt@cisco.com","published_at":"2021-10-06 20:15:00","updated_at":"2023-11-07 03:28:00"},"problem_types":["NVD-CWE-noinfo"],"metrics":[],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-url-bypass-sGcfsDrp","name":"20211006 Cisco Email Security Appliance URL Filtering Bypass Vulnerability","refsource":"CISCO","tags":[],"title":"Cisco Email Security Appliance URL Filtering Bypass Vulnerability","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-1534","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-1534","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"1534","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"cisco","cpe5":"asyncos","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c170","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c190","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c380","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c390","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c680","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c690","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"1534","vulnerable":"-1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"h","cpe4":"cisco","cpe5":"email_security_appliance_c690x","cpe6":"-","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-1534","qid":"317073","title":"Cisco Email Security Appliance (ESA) Uniform Resource Locator (URL) Filtering Bypass Vulnerability (cisco-sa-esa-url-bypass-sGcfsDrp)"}]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"psirt@cisco.com","DATE_PUBLIC":"2021-10-06T16:00:00","ID":"CVE-2021-1534","STATE":"PUBLIC","TITLE":"Cisco Email Security Appliance URL Filtering Bypass Vulnerability"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"Cisco Email Security Appliance (ESA) ","version":{"version_data":[{"version_value":"n/a"}]}}]},"vendor_name":"Cisco"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device."}]},"exploit":[{"lang":"eng","value":"The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory. "}],"impact":{"cvss":{"baseScore":"5.8","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N ","version":"3.0"}},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-20"}]}]},"references":{"reference_data":[{"name":"20211006 Cisco Email Security Appliance URL Filtering Bypass Vulnerability","refsource":"CISCO","url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-url-bypass-sGcfsDrp"}]},"source":{"advisory":"cisco-sa-esa-url-bypass-sGcfsDrp","defect":[["CSCvx60178"]],"discovery":"INTERNAL"}},"nvd":{"publishedDate":"2021-10-06 20:15:00","lastModifiedDate":"2023-11-07 03:28:00","problem_types":["NVD-CWE-noinfo"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM"},"exploitabilityScore":3.9,"impactScore":1.4},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:L/Au:N/C:N/I:P/A:N","accessVector":"NETWORK","accessComplexity":"LOW","authentication":"NONE","confidentialityImpact":"NONE","integrityImpact":"PARTIAL","availabilityImpact":"NONE","baseScore":5},"severity":"MEDIUM","exploitabilityScore":10,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"AND","children":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*","versionEndExcluding":"14.0.1","cpe_name":[]}]},{"operator":"OR","children":[],"cpe_match":[{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c170:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c190:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c380:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c390:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c680:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c690:-:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":false,"cpe23Uri":"cpe:2.3:h:cisco:email_security_appliance_c690x:-:*:*:*:*:*:*:*","cpe_name":[]}]}],"cpe_match":[]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"1534","Ordinal":"191607","Title":"CVE-2021-1534","CVE":"CVE-2021-1534","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"1534","Ordinal":"1","NoteData":"A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way. A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"1534","Ordinal":"2","NoteData":"2021-10-06","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"1534","Ordinal":"3","NoteData":"2021-10-06","Type":"Other","Title":"Modified"}]}}}