{"id":"CVE-2017-3737","url":"https://www.cyber-defence.io/tools/cve/CVE-2017-3737","generatedAt":"2026-10-29T01:41:48.111Z","title":"OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an \"error state\" mechanism.","description":"OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an \"error state\" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.","published":"2017-12-07T16:29:00.000Z","lastModified":"2026-06-17T01:18:49.000Z","status":"Modified","sourceIdentifier":"openssl-security@openssl.org","cvss":{"version":"3.0","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-125","CWE-787"],"affected":["openssl/openssl","debian/debian linux"],"epss":{"score":0.78675,"percentile":0.99585,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 78.7%, higher than 100% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html","source":"openssl-security@openssl.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html","source":"openssl-security@openssl.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html","source":"openssl-security@openssl.org"},{"url":"http://www.securityfocus.com/bid/102103","tags":["Third Party Advisory","VDB Entry"],"source":"openssl-security@openssl.org"},{"url":"http://www.securitytracker.com/id/1039978","tags":["Third Party Advisory","VDB Entry"],"source":"openssl-security@openssl.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:0998","source":"openssl-security@openssl.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:2185","source":"openssl-security@openssl.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:2186","source":"openssl-security@openssl.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:2187","source":"openssl-security@openssl.org"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-179516.pdf","source":"openssl-security@openssl.org"},{"url":"https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc","source":"openssl-security@openssl.org"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-17:12.openssl.asc","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.gentoo.org/glsa/201712-03","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20171208-0001/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20180117-0002/","source":"openssl-security@openssl.org"},{"url":"https://security.netapp.com/advisory/ntap-20180419-0002/","source":"openssl-security@openssl.org"},{"url":"https://www.debian.org/security/2017/dsa-4065","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.digitalmunition.me/2017/12/cve-2017-3737-openssl-security-bypass-vulnerability/","tags":["Third Party Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.openssl.org/news/secadv/20171207.txt","tags":["Vendor Advisory"],"source":"openssl-security@openssl.org"},{"url":"https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html","source":"openssl-security@openssl.org"},{"url":"https://www.tenable.com/security/tns-2017-16","source":"openssl-security@openssl.org"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/102103","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1039978","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:0998","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:2185","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:2186","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:2187","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/pdf/ssa-179516.pdf","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.FreeBSD.org/advisories/FreeBSD-SA-17:12.openssl.asc","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/201712-03","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20171208-0001/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20180117-0002/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20180419-0002/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2017/dsa-4065","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.digitalmunition.me/2017/12/cve-2017-3737-openssl-security-bypass-vulnerability/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.openssl.org/news/secadv/20171207.txt","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.tenable.com/security/tns-2017-16","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2017-3737","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}