ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service…
Priority MEDIUM 50CWE-287Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-287.
Summary
ntpd in NTP 4.x before 4.2.8p8 allows remote attackers to cause a denial of service (ephemeral-association demobilization) by sending a spoofed crypto-NAK packet with incorrect authentication data at a certain time.
Why it matters now
EPSS 0.17245 97th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 40
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:* | 4.2.0 to before 4.2.8; 4.3.0 to before 4.3.93 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:* | 4.2.8 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:* | 4.2.8 p1 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:* | 4.2.8 p1-beta1 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-beta2:*:*:*:*:*:* | 4.2.8 p1-beta2 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-beta3:*:*:*:*:*:* | 4.2.8 p1-beta3 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-beta4:*:*:*:*:*:* | 4.2.8 p1-beta4 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-beta5:*:*:*:*:*:* | 4.2.8 p1-beta5 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-rc1:*:*:*:*:*:* | 4.2.8 p1-rc1 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p1-rc2:*:*:*:*:*:* | 4.2.8 p1-rc2 | Vulnerable | NTP Project |
- cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:* Versions 4.2.0 to before 4.2.8; 4.3.0 to before 4.3.93 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:* Versions 4.2.8 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:* Versions 4.2.8 p1 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:* Versions 4.2.8 p1-beta1 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-beta2:*:*:*:*:*:* Versions 4.2.8 p1-beta2 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-beta3:*:*:*:*:*:* Versions 4.2.8 p1-beta3 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-beta4:*:*:*:*:*:* Versions 4.2.8 p1-beta4 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-beta5:*:*:*:*:*:* Versions 4.2.8 p1-beta5 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-rc1:*:*:*:*:*:* Versions 4.2.8 p1-rc1 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p1-rc2:*:*:*:*:*:* Versions 4.2.8 p1-rc2 Vulnerable ·NTP Project
Show 30 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:ntp:ntp:4.2.8:p2:*:*:*:*:*:* | 4.2.8 p2 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p2-rc1:*:*:*:*:*:* | 4.2.8 p2-rc1 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p2-rc2:*:*:*:*:*:* | 4.2.8 p2-rc2 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p2-rc3:*:*:*:*:*:* | 4.2.8 p2-rc3 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p3:*:*:*:*:*:* | 4.2.8 p3 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p3-rc1:*:*:*:*:*:* | 4.2.8 p3-rc1 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p3-rc2:*:*:*:*:*:* | 4.2.8 p3-rc2 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p3-rc3:*:*:*:*:*:* | 4.2.8 p3-rc3 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:* | 4.2.8 p4 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p5:*:*:*:*:*:* | 4.2.8 p5 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p6:*:*:*:*:*:* | 4.2.8 p6 | Vulnerable | NTP Project |
| cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:* | 4.2.8 p7 | Vulnerable | NTP Project |
| cpe:2.3:o:oracle:solaris:10:*:*:*:*:*:*:* | 10 | Vulnerable | Oracle |
| cpe:2.3:o:oracle:solaris:11.3:*:*:*:*:*:*:* | 11.3 | Vulnerable | Oracle |
| cpe:2.3:a:suse:manager:2.1:*:*:*:*:*:*:* | 2.1 | Vulnerable | SUSE |
| cpe:2.3:a:suse:manager_proxy:2.1:*:*:*:*:*:*:* | 2.1 | Vulnerable | SUSE |
| cpe:2.3:a:suse:openstack_cloud:5:*:*:*:*:*:*:* | 5 | Vulnerable | SUSE |
| cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:* | 42.1 | Vulnerable | openSUSE |
| cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:* | 13.2 | Vulnerable | openSUSE |
| cpe:2.3:o:suse:linux_enterprise_desktop:12:sp1:*:*:*:*:*:* | 12 sp1 | Vulnerable | SUSE |
| cpe:2.3:o:suse:linux_enterprise_server:11:sp2:*:*:ltss:*:*:* | 11 sp2 | Vulnerable | SUSE |
| cpe:2.3:o:suse:linux_enterprise_server:11:sp3:*:*:ltss:*:*:* | 11 sp3 | Vulnerable | SUSE |
| cpe:2.3:o:suse:linux_enterprise_server:11:sp4:*:*:*:*:*:* | 11 sp4 | Vulnerable | SUSE |
| cpe:2.3:o:suse:linux_enterprise_server:12:sp1:*:*:*:*:*:* | 12 sp1 | Vulnerable | SUSE |
| cpe:2.3:o:siemens:simatic_net_cp_443-1_opc_ua_firmware:*:*:*:*:*:*:*:* | all versions | Vulnerable | Siemens |
| cpe:2.3:h:siemens:simatic_net_cp_443-1_opc_ua:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Siemens |
| cpe:2.3:o:siemens:tim_4r-ie_firmware:*:*:*:*:*:*:*:* | all versions | Vulnerable | Siemens |
| cpe:2.3:h:siemens:tim_4r-ie:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Siemens |
| cpe:2.3:o:siemens:tim_4r-ie_dnp3_firmware:*:*:*:*:*:*:*:* | all versions | Vulnerable | Siemens |
| cpe:2.3:h:siemens:tim_4r-ie_dnp3:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Siemens |
- cpe:2.3:a:ntp:ntp:4.2.8:p2:*:*:*:*:*:* Versions 4.2.8 p2 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p2-rc1:*:*:*:*:*:* Versions 4.2.8 p2-rc1 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p2-rc2:*:*:*:*:*:* Versions 4.2.8 p2-rc2 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p2-rc3:*:*:*:*:*:* Versions 4.2.8 p2-rc3 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p3:*:*:*:*:*:* Versions 4.2.8 p3 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p3-rc1:*:*:*:*:*:* Versions 4.2.8 p3-rc1 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p3-rc2:*:*:*:*:*:* Versions 4.2.8 p3-rc2 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p3-rc3:*:*:*:*:*:* Versions 4.2.8 p3-rc3 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:* Versions 4.2.8 p4 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p5:*:*:*:*:*:* Versions 4.2.8 p5 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p6:*:*:*:*:*:* Versions 4.2.8 p6 Vulnerable ·NTP Project
- cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:* Versions 4.2.8 p7 Vulnerable ·NTP Project
- cpe:2.3:o:oracle:solaris:10:*:*:*:*:*:*:* Versions 10 Vulnerable ·Oracle
- cpe:2.3:o:oracle:solaris:11.3:*:*:*:*:*:*:* Versions 11.3 Vulnerable ·Oracle
- cpe:2.3:a:suse:manager:2.1:*:*:*:*:*:*:* Versions 2.1 Vulnerable ·SUSE
- cpe:2.3:a:suse:manager_proxy:2.1:*:*:*:*:*:*:* Versions 2.1 Vulnerable ·SUSE
- cpe:2.3:a:suse:openstack_cloud:5:*:*:*:*:*:*:* Versions 5 Vulnerable ·SUSE
- cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:* Versions 42.1 Vulnerable ·openSUSE
- cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:* Versions 13.2 Vulnerable ·openSUSE
- cpe:2.3:o:suse:linux_enterprise_desktop:12:sp1:*:*:*:*:*:* Versions 12 sp1 Vulnerable ·SUSE
- cpe:2.3:o:suse:linux_enterprise_server:11:sp2:*:*:ltss:*:*:* Versions 11 sp2 Vulnerable ·SUSE
- cpe:2.3:o:suse:linux_enterprise_server:11:sp3:*:*:ltss:*:*:* Versions 11 sp3 Vulnerable ·SUSE
- cpe:2.3:o:suse:linux_enterprise_server:11:sp4:*:*:*:*:*:* Versions 11 sp4 Vulnerable ·SUSE
- cpe:2.3:o:suse:linux_enterprise_server:12:sp1:*:*:*:*:*:* Versions 12 sp1 Vulnerable ·SUSE
- cpe:2.3:o:siemens:simatic_net_cp_443-1_opc_ua_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Siemens
- cpe:2.3:h:siemens:simatic_net_cp_443-1_opc_ua:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Siemens
- cpe:2.3:o:siemens:tim_4r-ie_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Siemens
- cpe:2.3:h:siemens:tim_4r-ie:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Siemens
- cpe:2.3:o:siemens:tim_4r-ie_dnp3_firmware:*:*:*:*:*:*:*:* Versions all versions Vulnerable ·Siemens
- cpe:2.3:h:siemens:tim_4r-ie_dnp3:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Siemens
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
Not affected: 3 products
- Red Hat Enterprise Linux 5
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2016-4953
- 2026-10-03 Alias added: GHSA-26jw-7mv6-89rj
References
Advisory 20
- SUSE-SU-2016:1602
- openSUSE-SU-2016:1583
- FreeBSD-SA-16:24
- SUSE-SU-2016:1912
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03757en_us
- SUSE-SU-2016:1584
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- SUSE-SU-2016:2094
- VU#321640
- http://support.ntp.org/bin/view/Main/SecurityNotice
- http://bugs.ntp.org/3045
- openSUSE-SU-2016:1636
- SUSE-SU-2016:1563
- GLSA-201607-15
- 20160603 Multiple Vulnerabilities in Network Time Protocol Daemon Affecting Cisco Products: June 2016
- SUSE-SU-2016:1568
- VU#321640
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
Sources
- CVE-2016-4953 · CVE Program
- CVE-2016-4953 · NVD
- FIRST EPSS
- GHSA-26jw-7mv6-89rj · GitHub Advisory Database · CC BY 4.0
- CVE-2016-4953 · Red Hat security data · CC BY 4.0
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