Improper handling of NTS cookie length that could crash the ntpd-rs server

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2023-33192: 0.71% estimated exploitation activity in the next 30 days; percentile 53.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact 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. ntpd-rs running purely as an ntp client is not affected. Patches 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 Workarounds ntpd-rs running purely as an ntp client is not affected. By default, ntpd-rs packages are not configured to run as a server. For machines where serving the time is required, there is no known workaround. Users are recommended to upgrade ntpd-rs as soon as possible. References https://github.com/pendulum-project/ntpd-rs/pull/752 We would like to thank @mlichvar for…

Published by the source

25 May 2023, 17:01 UTC

Last modified by the source

4 Nov 2023, 05:04 UTC

Source last checked

26 Oct 2026, 15:37 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-qwhm-h7v3-mrjx

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# Patch Next advisory brief: CVE-2023-33192

Advisory: Improper handling of NTS cookie length that could crash the ntpd-rs server
IDs: CVE-2023-33192, GHSA-qwhm-h7v3-mrjx
Record: https://patchnext.com/advisories/cve-2023-33192 (revision 1, source checked 26 Oct 2026, 15:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ntpd 0.3.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io ntpd: affected >= 0.3.0, < 0.3.3; fixed in 0.3.3

## Suggested inspection (read-only)
- crates.io ntpd: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ntpd.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-qwhm-h7v3-mrjx (GitHub-reviewed advisory GHSA-qwhm-h7v3-mrjx lists affected ranges: crates.io ntpd >=0.3.0 <0.3.3)

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