# CVE-2018-0061: Junos OS: Denial of service in telnetd

> Remote unauthenticated attackers can cause high CPU usage in the telnetd service, leading to system performance degradation or denial of service.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Oct 2018
- **Updated:** 17 Sep 2024
- **Also known as:** GHSA-mg2c-wjpf-6pjp

## What is CVE-2018-0061?

CVE-2018-0061 is a medium-severity denial of service vulnerability in Juniper Junos, published on 10 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A denial of service vulnerability in the telnetd service on Junos OS allows remote unauthenticated users to cause high CPU usage which may affect system performance. Affected releases are Juniper Networks Junos OS: 12.1X46 versions prior to 12.1X46-D81 on SRX Series; 12.3 versions prior to 12.3R12-S11; 12.3X48 versions prior to 12.3X48-D80 on SRX Series; 15.1 versions prior to 15.1R7; 15.1X49 versions prior to 15.1X49-D150, 15.1X49-D160 on SRX Series; 15.1X53 versions prior to 15.1X53-D59 on EX2300/EX3400 Series; 15.1X53 versions prior to 15.1X53-D68 on QFX10K Series; 15.1X53 versions prior to 15.1X53-D235 on QFX5200/QFX5110 Series; 15.1X53 versions prior to 15.1X53-D495 on NFX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6, 16.1R7; 16.2 versions prior to 16.2R2-S7, 16.2R3; 17.1 versions prior to 17.1R2-S9, 17.1R3; 17.2 versions prior to 17.2R2-S6, 17.2R3; 17.2X75 versions prior to 17.2X75-D100; 17.3 versions prior to 17.3R2-S4, 17.3R3; 17.4 versions prior to 17.4R1-S5, 17.4R2; 18.2X75 versions prior to 18.2X75-D5.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-0061?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2018-0061?

No fix has been published for CVE-2018-0061 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-0061 being exploited?

There is no known exploitation of CVE-2018-0061 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-2018-0061 and fix it if it is affected.

What it is: CVE-2018-0061 is a medium-severity denial of service vulnerability in Juniper Junos, published on 10 Oct 2018. 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-2018-0061 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-2018-0061/ (Markdown: https://insights.sbomify.com/CVE-2018-0061/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0061
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0061
- OSV: https://osv.dev/vulnerability/CVE-2018-0061

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-0061/
Summaries are generated and may contain mistakes; the official description above is the record.