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instructions.","known_ransomware_use":"Known"},"exploitation":[{"source":"euvd","since":"2021-11-03"},{"source":"kev","since":"2021-11-03"}],"exploits":[{"source":"pocgithub","id":"sirpedrotavares/Proxylogon-exploit","title":"sirpedrotavares/Proxylogon-exploit","date":"2021-03-11","url":"https://github.com/sirpedrotavares/Proxylogon-exploit"}],"products":[{"vendor":"microsoft","product":"exchange server"},{"vendor":"microsoft","product":"exchange_server"},{"vendor":"microsoft","product":"microsoft exchange server 2010 service pack 3"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 21"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 22"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 23"},{"vendor":"microsoft","product":"microsoft exchange server 2013 service pack 1"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 10"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 11"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 12"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 13"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 14"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 15"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 16"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 17"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 18"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 19"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 8"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 9"},{"vendor":"microsoft","product":"microsoft exchange server 2019"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 1"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 2"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 3"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 4"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 5"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 6"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 7"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 8"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26857","tags":["vendor-advisory","patch","Patch","Vendor Advisory"]},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26857","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26857","tags":["government-resource","US Government Resource"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-26857"},{"url":"https://github.com/advisories/GHSA-2qwq-gqpm-q83g"}],"sources":{"cve":[{"id":"CVE-2021-26857","title":"Microsoft Exchange Server Remote Code Execution Vulnerability","description":"Microsoft Exchange Server Remote Code Execution Vulnerability","status":"published","published":"2021-03-02T23:55:26Z","modified":"2026-08-19T16:30:15.844Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C","level":"high","assessor":"cna"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:32:57.033395Z"}],"euvd":[{"id":"EUVD-2021-13641","description":"Microsoft Exchange Server Remote Code Execution Vulnerability","status":"published","published":"2021-03-02T23:55:26Z","modified":"2026-08-19T16:30:15Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C","level":"high"}],"exploited_since":"2021-11-03","updated_at":"2026-11-02T18:01:42.811156Z"}],"ghsa":[{"id":"GHSA-2qwq-gqpm-q83g","title":"Rails is bad","description":"Microsoft Exchange Server Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26858, CVE-2021-27065, CVE-2021-27078.","status":"published","published":"2022-05-24T22:01:28Z","modified":"2026-08-19T18:32:31Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-502","CWE-506"],"updated_at":"2026-11-02T15:10:42.300371Z"}],"kev":[{"id":"CVE-2021-26857","title":"Microsoft Exchange Server Remote Code Execution Vulnerability","description":"Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain.","cwes":["CWE-502"],"kev":{"date_added":"2021-11-03","due_date":"2022-05-03","required_action":"Apply updates per vendor instructions.","known_ransomware_use":"Known"},"updated_at":"2026-11-02T17:00:17.050017Z"}],"nvd":[{"id":"CVE-2021-26857","description":"Microsoft Exchange Server Remote Code Execution Vulnerability","status":"published","published":"2021-03-03T00:15:12.167Z","modified":"2026-08-19T19:22:27.153Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:06:50.399901Z"}]}}