# CVE-2019-1965: Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability

> Authenticated remote attackers can cause a system-wide denial of service by triggering a memory leak in Cisco NX-OS VSH session management.

- **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:** 28 Aug 2019
- **Updated:** 21 Nov 2024
- **Also known as:** GHSA-6q32-36x4-ww95

## What is CVE-2019-1965?

CVE-2019-1965 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 28 Aug 2019. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH process to fail to delete upon termination. This can lead to a build-up of VSH processes that overtime can deplete system memory. When there is no system memory available, this can cause unexpected system behaviors and crashes. The vulnerability is due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly performing a remote management connection to the device and terminating the connection in an unexpected manner. A successful exploit could allow the attacker to cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition. The attacker must have valid user credentials to log in to the device using the remote management connection.

Weakness: CWE-772 (Missing Release of Resource after Effective Lifetime), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2019-1965?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2019-1965?

No fix has been published for CVE-2019-1965 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1965 being exploited?

There is no known exploitation of CVE-2019-1965 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-2019-1965 and fix it if it is affected.

What it is: CVE-2019-1965 is a high-severity denial of service vulnerability in Cisco Nx-Os, published on 28 Aug 2019. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-1965 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-2019-1965/ (Markdown: https://insights.sbomify.com/CVE-2019-1965/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1965
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1965
- OSV: https://osv.dev/vulnerability/CVE-2019-1965

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-1965/
Summaries are generated and may contain mistakes; the official description above is the record.