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5.9

CVE-2016-5117: OpenNTPD <6.0p1 may trust fake HTTPS certificates

CVE-2016-5117 · published 9 years ago
Summary

The OpenNTPD version shipped with Debian before 6.0p1 does not verify the certificate name when handling HTTPS time‑constraint requests. This allows an attacker to present a counterfeit certificate and intercept or alter time data without detection. Upgrade OpenNTPD to version 6.0p1 or later to restore proper certificate checks.

What to do
  • Update debian openntpd to version 1:6.0p1-1.
Affected software
Ecosystem VendorProductAffected versions
Debian:12 debian openntpd < 1:6.0p1-1
Fix: upgrade to 1:6.0p1-1
Debian:13 debian openntpd < 1:6.0p1-1
Fix: upgrade to 1:6.0p1-1
Debian:14 debian openntpd < 1:6.0p1-1
Fix: upgrade to 1:6.0p1-1
– openntpd openntpd <= 6.0
cpe:2.3:a:openntpd:openntpd:*:*:*:*:*:*:*:*
Original advisory text
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 val...
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.
Severity
5.9 Medium
Exploitation
<1% chance of attack within 30 days
Type
CWE-2547PK - Security Features
Timeline
Published31 Jan 2017
Updated4 Nov 2026
First seen22 Sep 2026
Sources
CVE-2016-5117 · NVD
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