CVE-2016-1547
An off-path attacker can cause a preemptible client association to be demobilized in NTP 4.2.8p4 and earlier and NTPSec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 by sending a crypto NAK packet to a victim client with a spoofed source address of an…
Does this matter?
Lower severity and a low EPSS score (5.07%). Track it; it rarely justifies an emergency change on its own.
Description
An off-path attacker can cause a preemptible client association to be demobilized in NTP 4.2.8p4 and earlier and NTPSec a5fb34b9cc89b92a8fef2f459004865c93bb7f92 by sending a crypto NAK packet to a victim client with a spoofed source address of an existing associated peer. This is true even if authentication is enabled.
- CVSS 3.0
- 5.3 MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 5.07% probability · 92th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- ntp/ntp
- Source
- cret@cert.org
EPSS 5.1% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://rhn.redhat.com/errata/RHSA-2016-1552.html
- http://www.debian.org/security/2016/dsa-3629
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- http://www.securityfocus.com/bid/88276
- http://www.securitytracker.com/id/1035705
- http://www.talosintelligence.com/reports/TALOS-2016-0081/Mitigation, Technical Description, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2016:1141
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:16.ntp.asc
- https://security.gentoo.org/glsa/201607-15
- https://security.netapp.com/advisory/ntap-20171004-0002/
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11
- https://www.arista.com/en/support/advisories-notices/security-advisories/1332-security-advisory-19
- http://rhn.redhat.com/errata/RHSA-2016-1552.html
- http://www.debian.org/security/2016/dsa-3629
- http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- http://www.securityfocus.com/bid/88276
- http://www.securitytracker.com/id/1035705
- http://www.talosintelligence.com/reports/TALOS-2016-0081/Mitigation, Technical Description, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2016:1141
- https://cert-portal.siemens.com/productcert/pdf/ssa-211752.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
- https://security.FreeBSD.org/advisories/FreeBSD-SA-16:16.ntp.asc
- https://security.gentoo.org/glsa/201607-15
- https://security.netapp.com/advisory/ntap-20171004-0002/
- https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11
- https://www.arista.com/en/support/advisories-notices/security-advisories/1332-security-advisory-19
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.