HIGH
CVE-2016-4957
CWE-476Published: July 5, 2016· Updated: Jun 17, 2026
7.5
CVSS v3.1
Official Description
ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.
Technical Analysis
CVE-2016-4957 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Vendors & Products
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
ADVISORYhttp://bugs.ntp.org/3046
ADVISORYhttp://bugs.ntp.org/3046
All References (26)
→
http://bugs.ntp.org/3046Issue Tracking · Vendor Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00023.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00024.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00028.htmlMailing List · Third Party Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00040.htmlMailing List · Third Party Advisory
→
http://support.ntp.org/bin/view/Main/NtpBug3046Patch · Vendor Advisory
→
http://support.ntp.org/bin/view/Main/SecurityNoticeRelease Notes · Vendor Advisory
→
http://www.kb.cert.org/vuls/id/321640Third Party Advisory · US Government Resource
→
http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.htmlThird Party Advisory
→
http://www.securitytracker.com/id/1036037Third Party Advisory · VDB Entry
→
https://security.FreeBSD.org/advisories/FreeBSD-SA-16:24.ntp.ascThird Party Advisory
→
https://security.gentoo.org/glsa/201607-15Third Party Advisory
→
http://bugs.ntp.org/3046Issue Tracking · Vendor Advisory
→
http://lists.opensuse.org/opensuse-security-announce/2016-06/msg00018.htmlMailing List · Third Party Advisory
Quick Facts
CVE IDCVE-2016-4957
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-476
CISA KEVNo
Affected5 vendor(s)
PublishedJul 5, 2016
Related CVEs (CWE-476)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2016-4957 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.