# CVE-2019-0031: Junos OS: jdhcpd daemon memory consumption Denial of Service when receiving specific IPv6 DHCP packets.

> Attackers can cause a Denial of Service in Junos OS by sending specific IPv6 DHCP packets to the jdhcpd daemon, exhausting memory resources.

- **Severity:** High 7.4 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Apr 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-r79h-x82m-qg3c

## What is CVE-2019-0031?

CVE-2019-0031 is a high-severity denial of service vulnerability in Juniper Junos, published on 10 Apr 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Specific IPv6 DHCP packets received by the jdhcpd daemon will cause a memory resource consumption issue to occur on a Junos OS device using the jdhcpd daemon configured to respond to IPv6 requests. Once started, memory consumption will eventually impact any IPv4 or IPv6 request serviced by the jdhcpd daemon, thus creating a Denial of Service (DoS) condition to clients requesting and not receiving IP addresses. Additionally, some clients which were previously holding IPv6 addresses will not have their IPv6 Identity Association (IA) address and network tables agreed upon by the jdhcpd daemon after the failover event occurs, which leads to more than one interface, and multiple IP addresses, being denied on the client. Affected releases are Juniper Networks Junos OS: 17.4 versions prior to 17.4R2; 18.1 versions prior to 18.1R2.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2019-0031?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2019-0031?

No fix has been published for CVE-2019-0031 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-0031 being exploited?

There is no known exploitation of CVE-2019-0031 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-0031 and fix it if it is affected.

What it is: CVE-2019-0031 is a high-severity denial of service vulnerability in Juniper Junos, published on 10 Apr 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-0031 in the wild and no public exploit code.

Affected product: Juniper Junos. 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-2019-0031/ (Markdown: https://insights.sbomify.com/CVE-2019-0031/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-0031
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-0031
- OSV: https://osv.dev/vulnerability/CVE-2019-0031

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-0031/
Summaries are generated and may contain mistakes; the official description above is the record.