CVE-2015-7855

MEDIUM

ntp 4.2.0-4.2.8 - Denial of Service via Long Data Value in Mode 6 or 7 Packet

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2015-7855. PoCs published by Magnus Klaaborg Stubman.

AI-analyzed exploit summary This exploit sends a malformed UDP packet to trigger a denial-of-service (DoS) condition in vulnerable versions of ntpd. The payload is crafted to exploit a buffer overflow in the NTP daemon, causing it to crash.

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.

Exploits (1)

exploitdb WORKING POC VERIFIED
by Magnus Klaaborg Stubman · pythondoslinux
https://www.exploit-db.com/exploits/40840

This exploit sends a malformed UDP packet to trigger a denial-of-service (DoS) condition in vulnerable versions of ntpd. The payload is crafted to exploit a buffer overflow in the NTP daemon, causing it to crash.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: ntpd versions up to 4.2.8p3 and 4.3.0 up to 4.3.77
No auth needed
Prerequisites: Network access to the target NTP server
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (11)

Core 11
Core References
Exploit, Third Party Advisory, VDB Entry exploit x_refsource_exploit-db
https://www.exploit-db.com/exploits/40840/
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/77283
Third Party Advisory, VDB Entry vdb-entry x_refsource_sectrack
http://www.securitytracker.com/id/1033951
Third Party Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2015/dsa-3388
Issue Tracking, Third Party Advisory, VDB Entry x_refsource_confirm
https://bugzilla.redhat.com/show_bug.cgi?id=1274264
Patch, Vendor Advisory x_refsource_confirm
http://support.ntp.org/bin/view/Main/NtpBug2922
Third Party Advisory, VDB Entry vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/201607-15
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20171004-0001/
Third Party Advisory x_refsource_confirm
https://cert-portal.siemens.com/productcert/pdf/ssa-497656.pdf
Third Party Advisory, US Government Resource x_refsource_confirm
https://us-cert.cisa.gov/ics/advisories/icsa-21-103-11

Scores

CVSS v3 6.5
EPSS 0.3107
EPSS Percentile 98.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-20
Status published
Products (12)
debian/debian_linux 7.0
debian/debian_linux 8.0
debian/debian_linux 9.0
netapp/clustered_data_ontap
netapp/data_ontap
netapp/oncommand_balance
netapp/oncommand_performance_manager
netapp/oncommand_unified_manager
ntp/ntp 4.2.8 (17 CPE variants)
ntp/ntp 4.2.0 - 4.2.8
... and 2 more
Published Aug 07, 2017
Tracked Since Feb 18, 2026