{"id":"CVE-2020-27121","aliases":["EUVD-2020-19645","GHSA-7c3f-h49g-4mg6"],"status":"published","title":"Cisco Unified Communications Manager IM and Presence Service Denial of Service Vulnerability","description":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM\u0026amp;P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.","severity":{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.01164,"percentile":0.67672,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-248","CWE-755"],"published":"2020-11-06T18:15:38Z","modified":"2026-06-17T03:08:49Z","products":[{"vendor":"cisco","product":"cisco unified communications manager im and presence service"},{"vendor":"cisco","product":"unified_communications_manager_im_and_presence_service"}],"references":[{"url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-imp-dos-uTx2dqu2","tags":["vendor-advisory","x_refsource_CISCO","x_transferred","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-27121"},{"url":"https://github.com/advisories/GHSA-7c3f-h49g-4mg6"}],"sources":{"cve":[{"id":"CVE-2020-27121","title":"Cisco Unified Communications Manager IM and Presence Service Denial of Service Vulnerability","description":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM\u0026amp;P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.","status":"published","published":"2020-11-06T18:15:38.587Z","modified":"2024-11-13T17:44:46.213Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-248"],"updated_at":"2026-11-02T14:35:53.236501Z"}],"euvd":[{"id":"EUVD-2020-19645","description":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM\u0026amp;P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.","status":"published","published":"2020-11-06T18:15:38Z","modified":"2024-11-13T17:44:46Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-03T00:05:02.084189Z"}],"ghsa":[{"id":"GHSA-7c3f-h49g-4mg6","title":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM...","description":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM\u0026amp;P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.","status":"published","published":"2022-05-24T17:33:19Z","modified":"2023-01-29T05:04:39Z","cwes":["CWE-755"],"updated_at":"2026-11-02T14:45:36.557586Z"}],"nvd":[{"id":"CVE-2020-27121","description":"A vulnerability in Cisco Unified Communications Manager IM \u0026amp; Presence Service (Unified CM IM\u0026amp;P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.","status":"published","published":"2020-11-06T19:15:13.36Z","modified":"2026-06-17T03:08:49.72Z","cvss":[{"version":"3.1","score":4.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-248","CWE-755"],"updated_at":"2026-11-02T14:06:21.80969Z"}]}}