How severe is GHSA-4855-q42w-5vr4?

GHSA-4855-q42w-5vr4 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-4855-q42w-5vr4?

GHSA-4855-q42w-5vr4 affects the following packages: ntpd-rs (crates.io). Ecosystems affected: crates.io.

How do I fix GHSA-4855-q42w-5vr4?

Update ntpd-rs to 1.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4855-q42w-5vr4 is resolved across your whole dependency graph.

How do I detect GHSA-4855-q42w-5vr4 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ntpd-rs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-4855-q42w-5vr4 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-4855-q42w-5vr4 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4855-q42w-5vr4 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-4855-q42w-5vr4?

GHSA-4855-q42w-5vr4 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 29th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-4855-q42w-5vr4?

GHSA-4855-q42w-5vr4 is classified as CWE-406 (CWE-406). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-4855-q42w-5vr4 published, and has it been updated?

GHSA-4855-q42w-5vr4 was published on August 29, 2025 and was last updated on August 29, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

MEDIUM severity

DoS Vulnerability in ntpd-rsGHSA-4855-q42w-5vr4

MEDIUMFix: pendulum-project/ntpd-rs@da37cf1

GHSA-4855-q42w-5vr4 is a medium-severity (CVSS 5.3) CWE-406 vulnerability in ntpd-rs. A fix is available for ntpd-rs — see the affected versions and patch details below.

Also known asCVE-2025-58066

Published

Aug 29, 2025

Updated

Aug 29, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-4855-q42w-5vr4.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk+0.02%

Lower risk than most CVEs29th percentile — riskier than 29% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🦀ntpd-rs

Real-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

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.

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.

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.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`ntpd-rs`	≥ 1.2.0&&< 1.6.2	1.6.2`cargo update -p ntpd-rs --precise 1.6.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ntpd-rs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ntpd-rs to 1.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4855-q42w-5vr4 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

# 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. # Impact Any time server running ntpd-rs with v