A malicious authenticated peer can create arbitrarily-many ephemeral associations in order to win the clock selection algorithm in ntpd in N
A malicious authenticated peer can create arbitrarily-many ephemeral associations in order to win the clock selection algorithm in ntpd in NTP 4.2.8p4 and earlier and NTPsec 3e160db8dc248a0bcb053b56a80167dc742d2b74 and a5fb34b9cc89b92a8fef2f459004865c93bb7f92 and modify a victim's clock.
- Published
- Jan 6, 2017
- Updated
- Jun 16, 2026
- EPSS
- 3.1% · 87th percentile
- CWE
- CWE-19
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.1%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| ntp | ntp | cpe:2.3:a:ntp:ntp |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- ntp ntp4.2.8
Versions reported by the vendor
Affected version ranges reported by the assigning authority (certcc). Independent of NVD's CPE analysis and usually ahead of it.
NTP Project NTP
- 4.2.8p3, 4.2.8p4affected
NTPsec Project NTPSec
- 3e160db8dc248a0bcb053b56a80167dc742d2b74, a5fb34b9cc89b92a8fef2f459004865c93bb7f92affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:11 | ntp | before 1:4.2.8p7+dfsg-1 | 1:4.2.8p7+dfsg-1 |
| SUSE:Linux Enterprise Desktop 12 | ntp | before 4.2.8p8-46.8.1 | 4.2.8p8-46.8.1 |
| SUSE:Linux Enterprise Desktop 12 SP3 | ntp | before 4.2.8p11-64.3.2 | 4.2.8p11-64.3.2 |
| SUSE:Linux Enterprise Server 11 SP4 | ntp | before 4.2.8p11-64.4.1 | 4.2.8p11-64.4.1 |
| SUSE:Linux Enterprise Server 11 SP4 | ntp | before 4.2.8p7-11.1 | 4.2.8p7-11.1 |
| SUSE:Linux Enterprise Server 12-LTSS | ntp | before 4.2.8p11-46.26.2 | 4.2.8p11-46.26.2 |
| SUSE:OpenStack Cloud 5 | ntp | before 4.2.8p7-44.1 | 4.2.8p7-44.1 |
| SUSE:OpenStack Cloud 7 | ntp | before 4.2.8p11-64.5.1 | 4.2.8p11-64.5.1 |
Same product
ntp: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-7871Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass authentication.64This week
- CVE-2014-9295Multiple stack-based buffer overflows in ntpd in NTP before 4.2.8 allow remote attackers to execute arbitrary code via a crafted packet, rel54Plan
- CVE-2013-5211The monlist feature in ntp_request.c in ntpd in NTP before 4.2.7p26 allows remote attackers to cause a denial of service (traffic amplificat49Plan
- CVE-2018-12327Stack-based buffer overflow in ntpq and ntpdc of NTP version 4.2.8p11 allows an attacker to achieve code execution or escalate to higher pri47Plan
- CVE-2016-7434The read_mru_list function in NTP before 4.2.8p9 allows remote attackers to cause a denial of service (crash) via a crafted mrulist query.46Plan
- CVE-2015-7853The datalen parameter in the refclock driver in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to execute arbitra43Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:ntp | 1:4.2.8p7+dfsg-1 · Debian:11 | Package registry (OSV) |
| suse:ntp | 4.2.8p7-11.1 · SUSE:Linux Enterprise Server 11 SP4 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-19 · Data Processing ErrorsCVSS vector
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- www.securityfocus.com/bid/88200
- www.securitytracker.com/id/1035705
- www.talosintelligence.com/reports/TALOS-2016-0083/
- security.FreeBSD.org/advisories/FreeBSD-SA-16:16.ntp.asc
- security.gentoo.org/glsa/201607-15
- security.netapp.com/advisory/ntap-20171004-0002/
- support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03962en_us
- www.synology.com/support/security/Synology_SA_18_13
Vendor advisories and official records. Exploit/PoC links are deliberately left out.