{"schemaVersion":3,"id":"CVE-2015-1637","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"Schannel (aka Secure Channel) in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly restrict TLS state transitions, which makes it easier for remote attackers to conduct cipher-downgrade attacks to EXPORT_RSA ciphers via crafted TLS traffic, related to the \"FREAK\" issue, a different vulnerability than CVE-2015-0204 and CVE-2015-1067.","dates":{"published":"2015-03-06T17:00:00.000Z","modified":"2024-08-06T04:47:17.473Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":4.3,"severity":"medium","version":"2.0","versionLabel":"v2.0","source":"NVD","vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"2.0","versionLabel":"v2.0","source":"NVD","score":4.3,"severity":"medium","vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.13151,"percentile":0.96331,"severity":"medium","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.13151},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.13151,"percentile":0.96331}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.13151,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.13151,"percentile":0.96331}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-310","name":"Cryptographic Issues","description":"Weaknesses in this category are related to the design and implementation of data confidentiality and integrity. Frequently these deal with the use of encoding techniques, encryption libraries, and hashing algorithms. The weaknesses in this category could lead to a degradation of the quality data if they are not addressed.","type":"category","status":"Draft","abstraction":null,"likelihoodOfExploit":null,"url":"https://cwe.mitre.org/data/definitions/310.html"}],"affected":[{"vendor":"microsoft","product":"windows_7","name":"windows 7","label":"windows_7","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_7"},{"vendor":"microsoft","product":"windows_8","name":"windows 8","label":"windows_8","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_8"},{"vendor":"microsoft","product":"windows_8.1","name":"windows 8.1","label":"windows_8.1","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_81"},{"vendor":"microsoft","product":"windows_rt","name":"windows rt","label":"windows_rt","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_rt"},{"vendor":"microsoft","product":"windows_rt_8.1","name":"windows rt 8.1","label":"windows_rt_8.1","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_rt_81"},{"vendor":"microsoft","product":"windows_server_2003","name":"windows server 2003","label":"windows_server_2003","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_server_2003"},{"vendor":"microsoft","product":"windows_server_2008","name":"windows server 2008","label":"windows_server_2008","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null},{"text":"r2:sp1","noFixRecorded":false,"fixedIn":null}],"versionsText":"na | r2:sp1","eol":null,"hubHref":"/vendor/microsoft/windows_server_2008"},{"vendor":"microsoft","product":"windows_server_2012","name":"windows server 2012","label":"windows_server_2012","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null},{"text":"r2","noFixRecorded":false,"fixedIn":null}],"versionsText":"na | r2","eol":null,"hubHref":"/vendor/microsoft/windows_server_2012"},{"vendor":"microsoft","product":"windows_vista","name":"windows vista","label":"windows_vista","ecosystem":null,"cpePart":"o","purl":null,"purlType":null,"versions":[{"text":"na","noFixRecorded":false,"fixedIn":null}],"versionsText":"na","eol":null,"hubHref":"/vendor/microsoft/windows_vista"}],"affectedCount":9,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://technet.microsoft.com/library/security/3046015","label":"technet.microsoft.com/library/security/3046015","hostname":"technet.microsoft.com","tags":["X Refsource CONFIRM","Patch","Vendor Advisory"]},{"url":"http://www.securitytracker.com/id/1031833","label":"www.securitytracker.com/id/1031833","hostname":"www.securitytracker.com","tags":["VDB Entry","X Refsource SECTRACK","Third Party Advisory"]},{"url":"http://www.securityfocus.com/bid/72965","label":"www.securityfocus.com/bid/72965","hostname":"www.securityfocus.com","tags":["VDB Entry","X Refsource BID","Third Party Advisory"]},{"url":"https://freakattack.com/","label":"freakattack.com","hostname":"freakattack.com","tags":["X Refsource MISC","Vendor Advisory"]},{"url":"https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-031","label":"docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-031","hostname":"docs.microsoft.com","tags":["Vendor Advisory","X Refsource MS","Patch"]},{"url":"http://web.archive.org/web/20150321220028/https://freakattack.com/","label":"web.archive.org/web/20150321220028/https://freakattack.com/","hostname":"web.archive.org","tags":["X Refsource MISC"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2015-03-06T17:00:00.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2024-08-06T04:47:17.473Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":20,"level":"low","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-19T18:03:10.829Z","stale":false,"partial":false}}