# CVE-2020-13817: Denial of service in n/a

> Remote attackers can cause NTP daemon exit or system time changes by spoofing packets if unauthenticated IPv4 sources are used.

- **Severity:** Medium 5.9 (`CVSS:3.0/AC:H/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Jun 2020
- **Updated:** 5 May 2025
- **Also known as:** CLSA-2024-1735122554, CLSA-2024-1735128099, CVE-2020-13816, DEBIAN-CVE-2020-13817, GHSA-fx6x-7xgx-2wwp, UBUNTU-CVE-2020-13817

## What is CVE-2020-13817?

CVE-2020-13817 is a medium-severity denial of service vulnerability in Netapp Cloud Backup, published on 4 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows remote attackers to cause a denial of service (daemon exit or system time change) by predicting transmit timestamps for use in spoofed packets. The victim must be relying on unauthenticated IPv4 time sources. There must be an off-path attacker who can query time from the victim's ntpd instance.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2020-13817?

It affects 25 products.


Products: Fujitsu M10-1 Firmware, Fujitsu M10-4 Firmware, Fujitsu M10-4s Firmware, Fujitsu M12-1 Firmware, Fujitsu M12-2 Firmware, Fujitsu M12-2s Firmware, Netapp Cloud Backup, Netapp Clustered Data Ontap, Netapp Data Ontap, Netapp Element Software, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410c Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware, Netapp Hci Compute Node Firmware, Netapp Hci Management Node and 5 more.

## How do I fix CVE-2020-13817?

Upgrade to a fixed version.

## Is CVE-2020-13817 being exploited?

There is no known exploitation of CVE-2020-13817 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-13817 and fix it if it is affected.

What it is: CVE-2020-13817 is a medium-severity denial of service vulnerability in Netapp Cloud Backup, published on 4 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-13817 in the wild and no public exploit code.

Affected product: Netapp Cloud Backup. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-13817/ (Markdown: https://insights.sbomify.com/CVE-2020-13817/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-13817
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-13817
- OSV: https://osv.dev/vulnerability/CVE-2020-13817

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-13817/
Summaries are generated and may contain mistakes; the official description above is the record.