ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause…
Priority LOW 38CWE-362Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Will not fix Red Hat: no fix planned
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
ntpd in NTP 4.x before 4.2.8p8, when autokey is enabled, allows remote attackers to cause a denial of service (peer-variable clearing and association outage) by sending (1) a spoofed crypto-NAK packet or (2) a packet with an incorrect MAC value at a certain time.
Why it matters now
EPSS 0.08771 95th percentileScored 2026-11-07
Fix Will not fix Red Hat: no fix planned
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 · 36
| 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 26 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_proxy:2.1:*:*:*:*:*:*:* | 2.1 | Vulnerable | SUSE |
| cpe:2.3:a:suse:openstack_cloud:5:*:*:*:*:*:*:* | 5 | Vulnerable | SUSE |
| cpe:2.3:o:novell:suse_manager:2.1:*:*:*:*:*:*:* | 2.1 | Vulnerable | Novell |
| 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: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_proxy:2.1:*:*:*:*:*:*:* Versions 2.1 Vulnerable ·SUSE
- cpe:2.3:a:suse:openstack_cloud:5:*:*:*:*:*:*:* Versions 5 Vulnerable ·SUSE
- cpe:2.3:o:novell:suse_manager:2.1:*:*:*:*:*:*:* Versions 2.1 Vulnerable ·Novell
- 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
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
Timeline
- 2026-10-02 Threatist record created from CVE-2016-4955
- 2026-10-03 Alias added: GHSA-c9r5-4837-463p
References
Advisory 21
- SUSE-SU-2016:1602
- USN-3096-1
- FEDORA-2016-c3bd6a3496
- openSUSE-SU-2016:1583
- FreeBSD-SA-16:24
- SUSE-SU-2016:1912
- FEDORA-2016-89e0874533
- SUSE-SU-2016:1584
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- SUSE-SU-2016:2094
- http://bugs.ntp.org/3043
- VU#321640
- http://support.ntp.org/bin/view/Main/SecurityNotice
- FEDORA-2016-50b0066b7f
- 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-211752.pdf
Sources
- CVE-2016-4955 · CVE Program
- CVE-2016-4955 · NVD
- FIRST EPSS
- GHSA-c9r5-4837-463p · GitHub Advisory Database · CC BY 4.0
- CVE-2016-4955 · Red Hat security data · CC BY 4.0
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