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Vulnerability record · CVE-2015-7855 · published 7 August 2017

CVE-2015-7855: Ntp improper input validation vulnerability

Ntp · Ntp

The decodenetnum function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (assertion failure) via a 6 or mode 7 packet containing a long data value.

6.5 CVSS 3.1 Medium EPSS 31% · top 1.8% CWE-20 · Improper input validation
6.5CVSS 3.1 base score, v2 4.0
31%EPSS exploitation probability, 30 days
NoNot in CISA KEV
9Affected product versions listed by NVD
22References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

The decodenetnum function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (assertion failure) via a 6 or mode 7 packet containing a long data value.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

9 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://support.ntp.org/bin/view/Main/NtpBug2922 PatchVendor Advisory
http://www.debian.org/security/2015/dsa-3388 Third Party Advisory
http://www.securityfocus.com/bid/77283 Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id/1033951 Third Party AdvisoryVDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=1274264 Issue TrackingThird Party AdvisoryVDB Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839 Third Party AdvisoryVDB Entry
https://security.gentoo.org/glsa/201607-15 Third Party AdvisoryVDB Entry
https://security.netapp.com/advisory/ntap-20171004-0001/ Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11 Third Party AdvisoryUS Government Resource
https://www.exploit-db.com/exploits/40840/ ExploitThird Party AdvisoryVDB Entry
http://support.ntp.org/bin/view/Main/NtpBug2922 PatchVendor Advisory
http://www.debian.org/security/2015/dsa-3388 Third Party Advisory
http://www.securityfocus.com/bid/77283 Third Party AdvisoryVDB Entry
http://www.securitytracker.com/id/1033951 Third Party AdvisoryVDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=1274264 Issue TrackingThird Party AdvisoryVDB Entry
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf Third Party Advisory
https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05270839 Third Party AdvisoryVDB Entry
https://security.gentoo.org/glsa/201607-15 Third Party AdvisoryVDB Entry
https://security.netapp.com/advisory/ntap-20171004-0001/ Third Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11 Third Party AdvisoryUS Government Resource
https://www.exploit-db.com/exploits/40840/ ExploitThird Party AdvisoryVDB Entry

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Source: NIST National Vulnerability Database (record CVE-2015-7855), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.