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Vulnerability record · CVE-2017-3733 · published 4 May 2017

CVE-2017-3733: Openssl improper input validation vulnerability

OOpenssl · Openssl

During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.

7.5 CVSS 3.0 High EPSS 13% · top 3.8% CWE-20 · Improper input validation
7.5CVSS 3.0 base score, v2 5.0
13%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
16References
17 Jun 2026Last modified by NVD

Description

During a renegotiation handshake if the Encrypt-Then-Mac extension is negotiated where it was not in the original handshake (or vice-versa) then this can cause OpenSSL 1.1.0 before 1.1.0e to crash (dependent on ciphersuite). Both clients and servers are affected.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
http://www.securityfocus.com/bid/96269 Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id/1037846
https://github.com/openssl/openssl/commit/4ad93618d26a3ea23d36ad5498ff4f59eff3a4d2
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbgn03728en_us Third Party AdvisoryVDB Entry
https://www.openssl.org/news/secadv/20170216.txt Vendor Advisory
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
http://www.securityfocus.com/bid/96269 Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id/1037846
https://github.com/openssl/openssl/commit/4ad93618d26a3ea23d36ad5498ff4f59eff3a4d2
https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbgn03728en_us Third Party AdvisoryVDB Entry
https://www.openssl.org/news/secadv/20170216.txt Vendor Advisory
https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2017-3733), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.