Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2015-7691

28
FAUCET Score

CVE-2015-7691 is a denial-of-service vulnerability in NTP versions 4.2.x before 4.2.8p4 and 4.3.x before 4.3.77, affecting products from vendors like Debian, NetApp, Oracle, and Red Hat. This flaw, an incomplete fix for CVE-2014-9750, allows remote attackers to crash the ntpd service by sending specially crafted packets related to autokey operations. With a CVSS score of 7.5 (HIGH), it presents a low-complexity network attack with a high impact on availability. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
>= 4.2.0, < 4.2.8CPE matchmatch criteria
cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
>= 4.3.0, < 4.3.77CPE matchmatch criteria
cpe:2.3:a:ntp:ntp:*:*:*:*:*:*:*:*
4.2.8CPE matchmatch criteria
cpe:2.3:a:ntp:ntp:4.2.8:-:*:*:*:*:*:*
4.2.8CPE matchmatch criteria
cpe:2.3:a:ntp:ntp:4.2.8:p1:*:*:*:*:*:*
4.2.8CPE matchmatch criteria
cpe:2.3:a:ntp:ntp:4.2.8:p1-beta1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
7.10%
Probability of exploitation in next 30 days
EPSS Percentile
93.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0710 is in the 89th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: ntp-0:4.2.6p5-10.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: ntp-0:4.2.6p5-25.el7
View patch
envoyvendor investigatingvia llm_extracted
mozillavendor investigatingvia llm_extracted
pythonvendor investigatingvia llm_extracted
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: ntp

Vendor Advisories (4)

mozillallm-mozilla-c998614f94f3422cHIGH

[R1] NTP Autokey Functionality Multiple Remote DoS

Oct 21, 2015
redhatCVE-2015-7691Moderate

ntp: incomplete checks in ntp_crypto.c

Oct 21, 2015
envoyllm-envoy-0b46313ca23c4fa9HIGH

[R1] NTP Autokey Functionality Multiple Remote DoS

Oct 21, 2015
pythonllm-python-44e897c0428dd381HIGH

[R1] NTP Autokey Functionality Multiple Remote DoS

Oct 21, 2015

References

rhn.redhat.com / errata/RHSA-2016-0780.html
Third Party Advisory
rhn.redhat.com / errata/RHSA-2016-2583.html
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party AdvisoryVDB Entry
security.gentoo.org / glsa/201607-15
Third Party AdvisoryVDB Entry
security.netapp.com / advisory/ntap-20171004-0001
Third Party Advisory
support.ntp.org / bin/view/Main/NtpBug2899
Vendor Advisory
debian.org / security/2015/dsa-3388
Third Party Advisory
oracle.com / technetwork/topics/security/linuxbulletinapr2016-2952096.html
Third Party Advisory
securityfocus.com / bid/77274
Third Party AdvisoryVDB Entry
securitytracker.com / id/1033951
Third Party AdvisoryVDB Entry