# CVE-2019-1901: Cisco Nexus 9000 Series ACI Mode Switch Software Link Layer Discovery Protocol Buffer Overflow Vulnerability

> Adjacent attackers can trigger a buffer overflow in LLDP processing to execute arbitrary code with root privileges or cause denial of service on Cisco Nexus ACI switches.

- **Severity:** High 8.8 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 31 Jul 2019
- **Updated:** 20 Nov 2024
- **Also known as:** GHSA-vrrp-56vv-xwg7

## What is CVE-2019-1901?

CVE-2019-1901 is a high-severity memory corruption vulnerability in Cisco Nx-Os, published on 31 Jul 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco Nexus 9000 Series Application Centric Infrastructure (ACI) Mode Switch Software could allow an adjacent, unauthenticated attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges. The vulnerability is due to improper input validation of certain type, length, value (TLV) fields of the LLDP frame header. An attacker could exploit this vulnerability by sending a crafted LLDP packet to the targeted device. A successful exploit may lead to a buffer overflow condition that could either cause a DoS condition or allow the attacker to execute arbitrary code with root privileges. Note: This vulnerability cannot be exploited by transit traffic through the device; the crafted packet must be targeted to a directly connected interface. This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI mode if they are running a Cisco Nexus 9000 Series ACI Mode Switch Software release prior to 13.2(7f) or any 14.x release.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2019-1901?

It affects 1 product.


Products: Cisco Nx-Os.

## How do I fix CVE-2019-1901?

No fix has been published for CVE-2019-1901 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1901 being exploited?

There is no known exploitation of CVE-2019-1901 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-2019-1901 and fix it if it is affected.

What it is: CVE-2019-1901 is a high-severity memory corruption vulnerability in Cisco Nx-Os, published on 31 Jul 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-2019-1901 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-2019-1901/ (Markdown: https://insights.sbomify.com/CVE-2019-1901/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1901
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1901
- OSV: https://osv.dev/vulnerability/CVE-2019-1901

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-1901/
Summaries are generated and may contain mistakes; the official description above is the record.