CVE-2015-1637

Name: CVE-2015-1637
Creator: NVD / NIST
Published: 2015-03-06T17:59:00.07+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 13.15%

Last modified Jun 17, 2026

CVE-2015-1637 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 13.15% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability

13.15%

95.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-310

Affected Software

Vendor	Product	Versions	Update
Microsoft	Windows 7	All versions	Sp1
Microsoft	Windows 8	All versions	—
Microsoft	Windows 8.1	All versions	—
Microsoft	Windows Rt	All versions	—
Microsoft	Windows Rt 8.1	All versions	—
Microsoft	Windows Server 2003	All versions	Sp2
Microsoft	Windows Server 2008	All versions	Sp2
Microsoft	Windows Server 2008	r2	Sp1
Microsoft	Windows Server 2012	All versions	—
Microsoft	Windows Server 2012	r2	—
Microsoft	Windows Vista	All versions	Sp2

References

http://web.archive.org/web/20150321220028/https://freakattack.com/
http://www.securityfocus.com/bid/72965Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1031833Third Party Advisory, VDB Entry
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-031Patch, Vendor Advisory
https://freakattack.com/Vendor Advisory
https://technet.microsoft.com/library/security/3046015Patch, Vendor Advisory
http://web.archive.org/web/20150321220028/https://freakattack.com/
http://www.securityfocus.com/bid/72965Third Party Advisory, VDB Entry
http://www.securitytracker.com/id/1031833Third Party Advisory, VDB Entry
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-031Patch, Vendor Advisory
https://freakattack.com/Vendor Advisory
https://technet.microsoft.com/library/security/3046015Patch, Vendor Advisory

Timeline

Published: Mar 6, 2015
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2015-1637?

How severe is CVE-2015-1637?

Severity scoring for CVE-2015-1637 is pending analysis. The EPSS model estimates a 13.15% probability of exploitation in the next 30 days.

How do I fix CVE-2015-1637?

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-2015-1637?

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

Scan your code now

Source: NVD / NIST