GHSA-qwhm-h7v3-mrjx is a high-severity (CVSS 7.5) CWE-130 vulnerability in ntpd. A fix is available for ntpd — see the affected versions and patch details below.
Improper handling of NTS cookie length that could crash the ntpd-rs server
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-qwhm-h7v3-mrjx.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-qwhm-h7v3-mrjx plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
ntpdReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.
Description
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 identifying this issue
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🦀crates.io | ntpd | ≥ 0.3.0&&< 0.3.3 | 0.3.3cargo update -p ntpd --precise 0.3.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ntpd, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ntpd to 0.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-qwhm-h7v3-mrjx is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-qwhm-h7v3-mrjx can be triaged on real exposure rather than presence alone.
Tailored to GHSA-qwhm-h7v3-mrjx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-qwhm-h7v3-mrjx in your dependencies?
O3 Security finds GHSA-qwhm-h7v3-mrjx across crates.io dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.