CVE-2016-5117
OpenNTPD before 6.0p1 does not validate the CN for HTTPS constraint requests, which allows remote...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2016-5117- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-254
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2016-5117- Updated
- 2026-11-02
EUVDEUVD-2016-6068 No score
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.
- Record
EUVD-2016-6068- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4m25-49gx-cpq6
OpenNTPD before 6.0p1 does not validate the CN for HTTPS constraint requests, which allows remote...
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.
- Record
GHSA-4m25-49gx-cpq6- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSV
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.
- Record
CVE-2016-5117- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2016-5117
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.
- Record
DEBIAN-CVE-2016-5117- CVSS 3.0
- 5.9 Medium
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2016-5117 is a medium vulnerability (CVSS 5.9) in Openntpd, published January 31, 2017. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.70%, the 53rd percentile. Fixed in openntpd 1:6.0p1-1.
References
cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.sbin/ntpd/constraint.c.diff?r1=1.27&r2=1.28
openwall.com/lists/oss-security/2016/05/23/2
openntpd.org/txt/release-6.0p1.txt
nvd.nist.gov/vuln/detail/CVE-2016-5117
github.com/advisories/GHSA-4m25-49gx-cpq6
security-tracker.debian.org/tracker/CVE-2016-5117