How severe is CVE-2020-13817?

CVE-2020-13817 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2020-13817 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-13817?

CVE-2020-13817 primarily affects Ntp. In total, 53 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-13817?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-13817 published?

CVE-2020-13817 was published on 2020-06-04 and last updated on 2026-06-17.

CVE-2020-13817

CVE-2020-13817 is a high-severity vulnerability in Ntp with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-330.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 5.8
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-330
Affected product: Ntp
Published: 2020-06-04
Last modified: 2026-06-17

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.

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.
How severe is CVE-2020-13817?: CVE-2020-13817 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2020-13817 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-13817?: CVE-2020-13817 primarily affects Ntp. In total, 53 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-13817?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-13817 published?: CVE-2020-13817 was published on 2020-06-04 and last updated on 2026-06-17.

References

Affected products (53)

cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta2:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta3:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta4:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta5:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-rc1:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p1-rc2:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p10:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p11:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p12:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p13:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p2:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p2-rc1:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p2-rc2:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p2-rc3:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p3:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p3-rc1:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p3-rc2:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p3-rc3:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p5:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p6:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p8:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.2.8:p9:*:*:*:*:*:*
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:data_ontap:-:*:*:*:*:7-mode:*:*
cpe:2.3:a:netapp:element_software:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:ontap_tools:-:*:*:*:*:vmware_vsphere:*:*
cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*
cpe:2.3:a:netapp:steelstore_cloud_integrated_storage:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*

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CVE-2015-7853 — Critical (CVSS 9.8): The 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…
CVE-2015-7705 — Critical (CVSS 9.8): The rate limiting feature in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to have unspecified…
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Threat intelligence

Threat-intel indicators referencing this CVE:

197.248.207.139 (ipv4-addr)
135.129.128.247 (ipv4-addr)
119.201.59.224 (ipv4-addr)
42.200.60.186 (ipv4-addr)
223.197.153.135 (ipv4-addr)
125.212.244.35 (ipv4-addr)
202.29.220.126 (ipv4-addr)
93.42.227.251 (ipv4-addr)