CVE-2016-5117

Name: CVE-2016-5117
Creator: NVD / NIST
Published: 2017-01-31T19:59:00.23+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 0.70%

Last modified Jun 17, 2026

CVE-2016-5117 is a vulnerability of currently unknown severity. OpenNTPD before 6.0p1 does not validate the CN for HTTPS constraint requests, which allows remote attackers to bypass the man-in-the-middle mitigations via a crafted timestamp constraint with a valid certificate.. EPSS estimates a 0.70% chance of exploitation in the next 30 days.

Description

OpenNTPD before 6.0p1 does not validate the CN for HTTPS constraint requests, which allows remote attackers to bypass the man-in-the-middle mitigations via a crafted timestamp constraint with a valid certificate.

Metrics

EPSS Probability

0.70%

48.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-254

Affected Software

Vendor	Product	Versions
Openntpd	Openntpd	<= 6.0

References

http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/constraint.c.diff?r1=1.27&r2=1.28Patch
http://www.openntpd.org/txt/release-6.0p1.txtVendor Advisory
http://www.openwall.com/lists/oss-security/2016/05/23/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2016/05/29/6Mailing List, Third Party Advisory
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/constraint.c.diff?r1=1.27&r2=1.28Patch
http://www.openntpd.org/txt/release-6.0p1.txtVendor Advisory
http://www.openwall.com/lists/oss-security/2016/05/23/2Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2016/05/29/6Mailing List, Third Party Advisory

Timeline

Published: Jan 31, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2016-5117?

How severe is CVE-2016-5117?

Severity scoring for CVE-2016-5117 is pending analysis. The EPSS model estimates a 0.70% probability of exploitation in the next 30 days.

How do I fix CVE-2016-5117?

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-2016-5117?

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

Scan your code now

Source: NVD / NIST