CVE-2015-7744

Name: CVE-2015-7744
Creator: NVD / NIST
Published: 2016-01-22T15:59:04.57+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 5.03%

Last modified Jun 17, 2026

CVE-2015-7744 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. wolfSSL (formerly CyaSSL) before 3.6.8 does not properly handle faults associated with the Chinese Remainder Theorem (CRT) process when allowing ephemeral key exchange without low memory optimizations on a server, which makes it easier for remote attackers to obtain private RSA keys by capturing TLS handshakes, aka a Lenstra attack.. EPSS estimates a 5.03% chance of exploitation in the next 30 days.

Description

wolfSSL (formerly CyaSSL) before 3.6.8 does not properly handle faults associated with the Chinese Remainder Theorem (CRT) process when allowing ephemeral key exchange without low memory optimizations on a server, which makes it easier for remote attackers to obtain private RSA keys by capturing TLS handshakes, aka a Lenstra attack.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

5.03%

91.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Wolfssl	Wolfssl	< 3.6.8
Opensuse	Leap	42.1
Opensuse	Opensuse	13.1
Opensuse	Opensuse	13.2
Mariadb	Mariadb	>= 5.5.0, < 5.5.46
Mariadb	Mariadb	>= 10.0.0, < 10.0.22
Mariadb	Mariadb	>= 10.1.0, < 10.1.9

References

http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00015.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00016.htmlMailing List, Third Party Advisory
http://wolfssl.com/wolfSSL/Docs-wolfssl-changelog.htmlRelease Notes, Vendor Advisory
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.htmlVendor Advisory
http://www.securitytracker.com/id/1034708Broken Link, Third Party Advisory, VDB Entry
https://people.redhat.com/~fweimer/rsa-crt-leaks.pdfExploit, Third Party Advisory
https://securityblog.redhat.com/2015/09/02/factoring-rsa-keys-with-tls-perfect-forward-secrecy/Exploit, Third Party Advisory
https://wolfssl.com/wolfSSL/Blog/Entries/2015/9/17_Two_Vulnerabilities_Recently_Found%2C_An_Attack_on_RSA_using_CRT_and_DoS_Vulnerability_With_DTLS.htmlVendor Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00015.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2016-02/msg00016.htmlMailing List, Third Party Advisory
http://wolfssl.com/wolfSSL/Docs-wolfssl-changelog.htmlRelease Notes, Vendor Advisory
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
http://www.oracle.com/technetwork/topics/security/cpujan2016-2367955.htmlVendor Advisory
http://www.securitytracker.com/id/1034708Broken Link, Third Party Advisory, VDB Entry
https://people.redhat.com/~fweimer/rsa-crt-leaks.pdfExploit, Third Party Advisory
https://securityblog.redhat.com/2015/09/02/factoring-rsa-keys-with-tls-perfect-forward-secrecy/Exploit, Third Party Advisory
https://wolfssl.com/wolfSSL/Blog/Entries/2015/9/17_Two_Vulnerabilities_Recently_Found%2C_An_Attack_on_RSA_using_CRT_and_DoS_Vulnerability_With_DTLS.htmlVendor Advisory

Timeline

Published: Jan 22, 2016
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2015-7744?

How severe is CVE-2015-7744?

CVE-2015-7744 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 5.03% probability of exploitation in the next 30 days.

How do I fix CVE-2015-7744?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2015-7744?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST