{"schemaVersion":3,"id":"CVE-2023-21529","aliases":[],"status":"published","duplicateOf":null,"title":"Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability","description":"Microsoft Exchange Server Remote Code Execution Vulnerability","dates":{"published":"2023-02-14T19:33:00.590Z","modified":"2026-08-19T16:26:33.854Z","reserved":null,"kevAdded":["2026-04-13T00:00:00.000Z"],"kevDue":["2026-04-27T00:00:00.000Z"]},"cvss":{"headline":{"score":8.8,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":8.8,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.59294,"percentile":0.99114,"severity":"critical","asOf":"2026-10-20T00:00:00.000Z","change":{"pp":-2.8100000000000014,"baselineDate":"2026-09-20T00:00:00.000Z","baselineScore":0.62104},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.59294,"percentile":0.99114}],"last30":[{"date":"2026-09-20T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.62104,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.59294,"percentile":null},{"date":"2026-10-20T00:00:00.000Z","score":0.59294,"percentile":0.99114}]},"kev":{"state":"listed","entries":[{"source":"cisa","sourceLabel":"CISA","dateAdded":"2026-04-13T00:00:00.000Z","dueDate":"2026-04-27T00:00:00.000Z","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","name":"Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability","description":"Microsoft Exchange Server contains a deserialization of untrusted data that allows an authenticated attacker to achieve remote code execution.","notes":[{"type":"url","href":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529","label":"msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2023-21529","label":"nvd.nist.gov/vuln/detail/CVE-2023-21529"}],"vendor":"Microsoft","product":"Exchange Server","ransomware":true,"ransomwareUse":"Known","exploitationType":null}],"listedCount":1,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":true,"entry":{"source":"cisa","sourceLabel":"CISA","dateAdded":"2026-04-13T00:00:00.000Z","dueDate":"2026-04-27T00:00:00.000Z","requiredAction":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.","name":"Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability","description":"Microsoft Exchange Server contains a deserialization of untrusted data that allows an authenticated attacker to achieve remote code execution.","notes":[{"type":"url","href":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529","label":"msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529"},{"type":"url","href":"https://nvd.nist.gov/vuln/detail/CVE-2023-21529","label":"nvd.nist.gov/vuln/detail/CVE-2023-21529"}],"vendor":"Microsoft","product":"Exchange Server","ransomware":true,"ransomwareUse":"Known","exploitationType":null}},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"known","sources":["cisa"]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-502","name":"Deserialization of Untrusted Data","description":"The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.","type":"weakness","status":"Draft","abstraction":"Base","likelihoodOfExploit":"Medium","url":"https://cwe.mitre.org/data/definitions/502.html"}],"affected":[{"vendor":"microsoft","product":"exchange_server","name":"Exchange Server","label":"exchange_server","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"2013:cumulative_update_23","noFixRecorded":false,"fixedIn":null},{"text":"2016:cumulative_update_23","noFixRecorded":false,"fixedIn":null},{"text":"2019:cumulative_update_11","noFixRecorded":false,"fixedIn":null},{"text":"2019:cumulative_update_12","noFixRecorded":false,"fixedIn":null}],"versionsText":"2013:cumulative_update_23 | 2016:cumulative_update_23 | 2019:cumulative_update_11 | 2019:cumulative_update_12","eol":{"isEol":null,"eolDate":null,"matchMethod":"cpe","cycle":null,"product":{"name":"msexchange","label":"Microsoft Exchange","category":"server-app"}},"hubHref":"/vendor/microsoft/exchange_server"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 23","name":"Microsoft Exchange Server 2013 Cumulative Update 23","label":"microsoft exchange server 2013 cumulative update 23","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 15.00.0, < 15.00.1497.047","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 15.00.0, < 15.00.1497.047","eol":null,"hubHref":"/vendor/microsoft/microsoft_exchange_server_2013_cumulative_update_23"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 23","name":"Microsoft Exchange Server 2016 Cumulative Update 23","label":"microsoft exchange server 2016 cumulative update 23","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 15.01.0, < 15.01.2507.021","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 15.01.0, < 15.01.2507.021","eol":null,"hubHref":"/vendor/microsoft/microsoft_exchange_server_2016_cumulative_update_23"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 11","name":"Microsoft Exchange Server 2019 Cumulative Update 11","label":"microsoft exchange server 2019 cumulative update 11","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 15.02.0, < 15.02.0986.041","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 15.02.0, < 15.02.0986.041","eol":null,"hubHref":"/vendor/microsoft/microsoft_exchange_server_2019_cumulative_update_11"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 12","name":"Microsoft Exchange Server 2019 Cumulative Update 12","label":"microsoft exchange server 2019 cumulative update 12","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 15.02.0, < 15.02.1118.025","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 15.02.0, < 15.02.1118.025","eol":null,"hubHref":"/vendor/microsoft/microsoft_exchange_server_2019_cumulative_update_12"}],"affectedCount":5,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529","label":"msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21529","hostname":"msrc.microsoft.com","tags":["Vendor Advisory","Patch"]},{"url":"https://www.microsoft.com/en-us/security/blog/2026/04/06/storm-1175-focuses-gaze-on-vulnerable-web-facing-assets-in-high-tempo-medusa-ransomware-operations/","label":"www.microsoft.com/en-us/…","hostname":"www.microsoft.com","tags":["Vendor Advisory","Technical Description"]},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529","label":"www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-21529","hostname":"www.cisa.gov","tags":["Government Resource","US Government Resource"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2023-02-14T19:33:00.590Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"kev-added","date":"2026-04-13T00:00:00.000Z","label":"Added to CISA KEV","detail":"Microsoft Exchange Server Deserialization of Untrusted Data Vulnerability","source":"cisa"},{"kind":"kev-due","date":"2026-04-27T00:00:00.000Z","label":"CISA remediation due","detail":"Apply mitigations per vendor instructions.","source":"cisa"},{"kind":"modified","date":"2026-08-19T16:26:33.854Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":90,"level":"critical","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-21T06:57:25.260Z","stale":false,"partial":false}}