# CVE-2018-0309: Denial of service in Cisco Nexus 3000 and 9000 unknown

> Authenticated attackers can cause a denial of service on Cisco Nexus switches by exhausting system memory via specific CLI commands or SNMP requests.

- **Severity:** High 7.7 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Jun 2018
- **Updated:** 29 Nov 2024
- **Also known as:** GHSA-57xh-q77w-pfgm

## What is CVE-2018-0309?

CVE-2018-0309 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 21 Jun 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability in the implementation of a specific CLI command and the associated Simple Network Management Protocol (SNMP) MIB for Cisco NX-OS (in standalone NX-OS mode) on Cisco Nexus 3000 and 9000 Series Switches could allow an authenticated, remote attacker to exhaust system memory on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to the incorrect implementation of the CLI command, resulting in a failure to free all allocated memory upon completion. An attacker could exploit this vulnerability by authenticating to the affected device and repeatedly issuing a specific CLI command or sending a specific SNMP poll request for a specific Object Identifier (OID). A successful exploit could allow the attacker to cause the IP routing process to restart or to cause a device reset, resulting in a DoS condition. Cisco Bug IDs: CSCvf23136.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2018-0309?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2018-0309?

No fix has been published for CVE-2018-0309 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-0309 being exploited?

There is no known exploitation of CVE-2018-0309 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Nx-Os

- [CVE-2024-20399](https://insights.sbomify.com/CVE-2024-20399/): Cisco NX-OS Command Injection (medium 6.0, exploited in the wild)
- [CVE-2021-1361](https://insights.sbomify.com/CVE-2021-1361/): Cisco NX-OS Software Unauthenticated Arbitrary File Actions Vulnerability (critical 9.8)
- [CVE-2018-0301](https://insights.sbomify.com/CVE-2018-0301/): Memory corruption in Cisco NX-OS unknown (critical 9.8)
- [CVE-2016-1453](https://insights.sbomify.com/CVE-2016-1453/): Memory corruption in n/a (critical 9.8)
- [CVE-2016-1341](https://insights.sbomify.com/CVE-2016-1341/): Hardcoded credentials in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-0309 and fix it if it is affected.

What it is: CVE-2018-0309 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 21 Jun 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-0309 in the wild and no public exploit code.

Affected product: Cisco Nx-Os. 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-2018-0309/ (Markdown: https://insights.sbomify.com/CVE-2018-0309/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0309
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0309
- OSV: https://osv.dev/vulnerability/CVE-2018-0309

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-0309/
Summaries are generated and may contain mistakes; the official description above is the record.