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No exploitation reportedFix available

CVE-2020-13817

No exploitation reported by the sources we read.

  • Published2020-06-04
  • Fixed in4.3.100 · 4.2.8
  • WeaknessCWE-330

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Timeline

dates in UTC
  1. 2020-06-0413:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-13817?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-13817?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Ntp
BranchAffectedFixed in
4.3≥ 4.3.0, < 4.3.1004.3.100
4.2< 4.2.84.2.8
4.2= 4.2.8no fix published
Fujitsu m10-4 firmwareversion to verify
BranchAffectedFixed in
—< xcp3110xcp3110
—< xcp2410xcp2410
Fujitsu m10-4s firmwareversion to verify
BranchAffectedFixed in
—< xcp3110xcp3110
—< xcp2410xcp2410

22 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Ntp to 4.3.100 · 4.2.8

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2025-04-23
  • OpenCVESSVC decisionnone—
  • CISA-ADPCVSS 3.17.42025-05-05
  • NVDCVSS 3.17.4read 2026-10-23
  • CNACVSS 3.05.9read 2026-10-23
  • NVDCVSS 2.05.8read 2026-10-23
  • CISA-ADPweakness (CWE)CWE-3302025-05-05
  • NVDweakness (CWE)CWE-330read 2026-10-23
  • FIRST EPSSEPSS score3.4 %2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
Published
2020-06-04
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-13817?

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Is CVE-2020-13817 actively exploited?

Active exploitation of CVE-2020-13817 has not been confirmed. Its EPSS score was 3.4% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-13817?

CVE-2020-13817 has a CVSS v3 base score of 7.4 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H.

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