Summary
A denial of service vulnerability was discovered in ntpd-rs where an attacker can induce a message storm between two NTP servers running ntpd-rs.
Details
Since ntpd-rs version 1.2.0, when configured as a server, incorrectly responded to all NTP messages sent to the server's port with a time reply, including to responses from other servers. As a consequence, a message with a spoofed IP address of another server could cause two servers running ntpd-rs to continually respond to each other, consuming significant amounts of resources.
Workarounds
Should upgrading not be possible, the impact of the issue can be mitigated by:
- Whitelisting access to only IP addresses of clients using the server, using the ignore filter method.
- Blocking incoming non-request traffic on the NTP server port using a firewall.
- Disabling public access to the vulnerable NTP server
- Disabling the server functionality by removing any [server] sections from the configuration.
Acknowledgements
The ntpd-rs authors thank Eric Sesterhenn from X41 D-Sec GmbH for finding and reporting this issue.
Impact
Any time server running ntpd-rs with version between 1.2.0 and 1.6.1 inclusive which allows non-NTS traffic is affected. Client-only configurations are not affected. Affected users are recommended to upgrade to version 1.6.2 as soon as possible.
CVE-2025-58066 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.6.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-58066? CVE-2025-58066 is a medium-severity security vulnerability in ntpd-rs (rust), affecting versions >= 1.2.0, < 1.6.2. It is fixed in 1.6.2.
- How severe is CVE-2025-58066? CVE-2025-58066 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of ntpd-rs are affected by CVE-2025-58066? ntpd-rs (rust) versions >= 1.2.0, < 1.6.2 is affected.
- Is there a fix for CVE-2025-58066? Yes. CVE-2025-58066 is fixed in 1.6.2. Upgrade to this version or later.
- Is CVE-2025-58066 exploitable, and should I be worried? Whether CVE-2025-58066 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-58066 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-58066? Upgrade
ntpd-rsto 1.6.2 or later.