{"id":"CVE-2021-27877","kind":"vulnerability","aliases":["CVE-2021-27877"],"related":[],"title":"An issue was discovered in Veritas Backup Exec before 21.2","description":"An issue was discovered in Veritas Backup Exec before 21.2. It supports multiple authentication schemes: SHA authentication is one of these. This authentication scheme is no longer used in current versions of the product, but hadn't yet been disabled. An attacker could remotely exploit this scheme to gain unauthorized access to an Agent and execute privileged commands.","summary":"Veritas Backup Exec Agent has an improper authentication flaw in its SHA authentication scheme. An attacker can gain unauthorized access to the agent on a backup host.","severity":"critical","cvss":9.8,"epss":null,"exploited":true,"exploited_at":"2023-04-07T00:00:00+00:00","products":[{"name":"Veritas Backup Exec Agent","fixed":[],"affected":"","ecosystem":"vendor"},{"name":"veritas backup exec","fixed":["21.2"],"affected":"< 21.2","ecosystem":"vendor"}],"ecosystems":["vendor"],"tags":["backup-exec","exploited","other","ransomware","veritas","windows"],"not_affected_if":["unknown"],"how_to_check":null,"fix":"Apply the vendor updates per Veritas instructions; CISA lists this as a known exploited vulnerability with required action to apply updates.","status":"open","published_at":"2021-03-01T22:15:14+00:00","first_seen_at":"2026-10-23T19:11:52+00:00","triaged_at":"2026-10-23T21:07:00+00:00","updated_at":"2026-10-23T22:29:04+00:00","category":"other","confidence":0.6,"triage":{"at":"2026-10-23T21:07:00Z","model":"claude-haiku-5-5","output":{"fix":"Apply the vendor updates per Veritas instructions; CISA lists this as a known exploited vulnerability with required action to apply updates.","reach":"network","impact":"high","summary":"Veritas Backup Exec Agent has an improper authentication flaw in its SHA authentication scheme. An attacker can gain unauthorized access to the agent on a backup host.","category":"other","who_cares":["veritas","backup-exec","windows"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Attacker gains unauthorized access to backup agent on the host","analyst_note":"Find affected and fixed Backup Exec Agent versions and the vendor advisory (Veritas security advisory for CVE-2021-27877) to fill in version and check fields.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":["unknown"],"user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"high"},"cost_usd":0.000449,"input_tokens":2819,"output_tokens":335,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2021':12A,15A '-27877':13A,16A '21.2':10A,68C 'access':51B,109C 'agent':20A,35B,54B,112C 'attack':47B,100C 'authent':39B,44B,72C,75C,81C 'backup':7A,18A,22A,25B,33B,57B,65C 'backup-exec':24B 'command':116C 'could':101C 'current':88C 'cve':11A,14A 'disabl':98C 'discov':4A,62C 'exec':8A,19A,23A,26B,34B,66C 'execut':114C 'exploit':27B,103C 'flaw':40B 'gain':49B,107C 'hadn':94C 'host':58B 'improp':38B 'issu':2A,60C 'longer':85C 'multipl':71C 'one':77C 'privileg':115C 'product':92C 'ransomwar':29B 'remot':102C 'scheme':45B,73C,82C,105C 'sha':43B,74C 'support':70C 'unauthor':50B,108C 'use':86C 'verita':6A,30B,32B,64C 'veritas':17A,21A 'version':89C 'window':31B 'yet':96C","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2021-03-01T22:15:14+00:00","kev":{"dateAdded":"2023-04-07","dueDate":"2023-04-28","requiredAction":"Apply updates per vendor instructions.","knownRansomwareCampaignUse":"Known"},"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N","cvss_by":"cve@mitre.org","poc_count":0,"sources":[{"source":"kev","external_id":"CVE-2021-27877","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27877","severity":null,"published_at":"2023-04-07T00:00:00+00:00","modified_at":null,"first_seen_at":"2026-10-23T19:11:52+00:00","fetched_at":"2026-10-25T13:39:30+00:00","note":null},{"source":"nvd","external_id":"CVE-2021-27877","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-27877","severity":null,"published_at":"2021-03-01T22:15:14+00:00","modified_at":"2026-06-17T03:45:32+00:00","first_seen_at":"2026-10-23T22:29:04+00:00","fetched_at":"2026-10-23T22:29:04+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}