{"cve":"CVE-2020-27121","nvd":{"published":"2020-11-06T19:15:13.360","modified":"2026-06-17T03:08:49.720","status":"Modified","description":"A vulnerability in Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-755","CWE-248"],"references":["https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-imp-dos-uTx2dqu2","https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-imp-dos-uTx2dqu2"],"products":["cisco:unified_communications_manager_im_and_presence_service"],"source":"nvd","synced_at":"2026-10-19T21:11:20.317016139+00:00"},"epss":{"cve":"CVE-2020-27121","score":0.01164,"percentile":0.67271,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}