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.

Published: 2020-06-04 Last update: 2025-05-05 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-13817 is rated Moderate Risk (49.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.35%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-13817

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-27 0.41% 0.35% -0.07%
2 2026-05-23 0.35% 0.41% +0.07%
3 2026-05-21 — 0.35% —

Full EPSS history (25 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-13817

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.2 [email protected]
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0
5.9 3.0 MEDIUM
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 3.6 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2020-13817

OS Trackers for CVE-2020-13817

vendor priority summary link
debian low CVE-2020-13817 low priority: Debian including 2 source packages (ntp, ntpsec), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2020-13817
gentoo normal CVE-2020-13817: 1 GLSA(s) (202007-12), 1 atom(s) (net-misc/ntp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-13817
redhat medium — https://access.redhat.com/security/cve/CVE-2020-13817
suse medium CVE-2020-13817 severity moderate: SUSE including 21 source package names (ntp-4.2.6p5-29.el7_8.2, ntp-4.2.8p15-4.10.1, …), 103 product×package rows across 69 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-Azure-BYOS, … (69 product lines)): Fixed 103. https://www.suse.com/security/cve/CVE-2020-13817/
ubuntu low CVE-2020-13817 low priority: Ubuntu including 1 source packages (ntp), 17 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 7, needs-triage 5, ignored 4, released 1. https://ubuntu.com/security/CVE-2020-13817

Affected software / configurations for CVE-2020-13817

Vendor Product Version Raw CPE
ntp ntp < 4.2.8 cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
ntp ntp >= 4.3.0, < 4.3.100 cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta4:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-beta5:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p1-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p10:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p11:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p12:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p13:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p2-rc3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc1:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc2:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p3-rc3:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p5:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p6:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p8:*:*:*:*:*:*
ntp ntp 4.2.8 cpe:2.3:a:ntp:ntp:4.2.8:p9:*:*:*:*:*:*
netapp cloud_backup — cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
netapp clustered_data_ontap — cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
netapp data_ontap — cpe:2.3:a:netapp:data_ontap:-:*:*:*:*:7-mode:*:*
netapp element_software — cpe:2.3:a:netapp:element_software:-:*:*:*:*:*:*:*
netapp hci_management_node — cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*
netapp ontap_tools — cpe:2.3:a:netapp:ontap_tools:-:*:*:*:*:vmware_vsphere:*:*
netapp solidfire — cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*
netapp steelstore_cloud_integrated_storage — cpe:2.3:a:netapp:steelstore_cloud_integrated_storage:-:*:*:*:*:*:*:*
netapp hci_compute_node_firmware — cpe:2.3:o:netapp:hci_compute_node_firmware:-:*:*:*:*:*:*:*
netapp h410c_firmware — cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:*
netapp h300s_firmware — cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*
netapp h500s_firmware — cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*
netapp h700s_firmware — cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*
netapp h300e_firmware — cpe:2.3:o:netapp:h300e_firmware:-:*:*:*:*:*:*:*
netapp h500e_firmware — cpe:2.3:o:netapp:h500e_firmware:-:*:*:*:*:*:*:*
netapp h700e_firmware — cpe:2.3:o:netapp:h700e_firmware:-:*:*:*:*:*:*:*
netapp h410s_firmware — cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
fujitsu m10-1_firmware < xcp2410 cpe:2.3:o:fujitsu:m10-1_firmware:*:*:*:*:*:*:*:*
fujitsu m10-4_firmware < xcp2410 cpe:2.3:o:fujitsu:m10-4_firmware:*:*:*:*:*:*:*:*
fujitsu m10-4s_firmware < xcp2410 cpe:2.3:o:fujitsu:m10-4s_firmware:*:*:*:*:*:*:*:*
fujitsu m12-1_firmware < xcp2410 cpe:2.3:o:fujitsu:m12-1_firmware:*:*:*:*:*:*:*:*
fujitsu m12-2_firmware < xcp2410 cpe:2.3:o:fujitsu:m12-2_firmware:*:*:*:*:*:*:*:*
fujitsu m12-2s_firmware < xcp2410 cpe:2.3:o:fujitsu:m12-2s_firmware:*:*:*:*:*:*:*:*
fujitsu m10-4_firmware < xcp3110 cpe:2.3:o:fujitsu:m10-4_firmware:*:*:*:*:*:*:*:*
fujitsu m10-4s_firmware < xcp3110 cpe:2.3:o:fujitsu:m10-4s_firmware:*:*:*:*:*:*:*:*
fujitsu m12-1_firmware < xcp3110 cpe:2.3:o:fujitsu:m12-1_firmware:*:*:*:*:*:*:*:*
fujitsu m12-2_firmware < xcp3110 cpe:2.3:o:fujitsu:m12-2_firmware:*:*:*:*:*:*:*:*
fujitsu m12-2s_firmware < xcp3110 cpe:2.3:o:fujitsu:m12-2s_firmware:*:*:*:*:*:*:*:*

References for CVE-2020-13817

cvelogic Threat Intelligence