{"id":"CVE-2021-34696","aliases":["EUVD-2021-21346","GHSA-28xr-x3rf-rhgr"],"status":"published","title":"Cisco ASR 900 and ASR 920 Series Aggregation Services Routers Access Control List Bypass Vulnerability","description":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.","severity":{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00999,"percentile":0.63242,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-284"],"published":"2021-09-23T02:25:30Z","modified":"2026-06-17T03:56:22Z","products":[{"vendor":"cisco","product":"cisco ios xe software"},{"vendor":"cisco","product":"ios_xe"}],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asr900acl-UeEyCxkv","tags":["vendor-advisory","x_refsource_CISCO","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-34696"},{"url":"https://github.com/advisories/GHSA-28xr-x3rf-rhgr"}],"sources":{"cve":[{"id":"CVE-2021-34696","title":"Cisco ASR 900 and ASR 920 Series Aggregation Services Routers Access Control List Bypass Vulnerability","description":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.","status":"published","published":"2021-09-23T02:25:30.776Z","modified":"2024-11-07T21:59:32.824Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:33:11.244759Z"}],"euvd":[{"id":"EUVD-2021-21346","description":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.","status":"published","published":"2021-09-23T02:25:30Z","modified":"2024-11-07T21:59:32Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","level":"medium"}],"updated_at":"2026-11-03T00:05:07.279991Z"}],"ghsa":[{"id":"GHSA-28xr-x3rf-rhgr","title":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series...","description":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.","status":"published","published":"2022-05-24T19:15:39Z","modified":"2023-01-30T05:02:26Z","updated_at":"2026-11-02T14:46:38.51672Z"}],"nvd":[{"id":"CVE-2021-34696","description":"A vulnerability in the access control list (ACL) programming of Cisco ASR 900 and ASR 920 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass a configured ACL. This vulnerability is due to incorrect programming of hardware when an ACL is configured using a method other than the configuration CLI. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an ACL on the affected device.","status":"published","published":"2021-09-23T03:15:15.633Z","modified":"2026-06-17T03:56:22.137Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:06:58.933037Z"}]}}