# CVE-2019-1756: Cisco IOS XE Software Command Injection Vulnerability

> Authenticated attackers can execute arbitrary root commands on Cisco IOS XE devices via malicious input in the web UI, leading to full system compromise.

- **Severity:** High 7.2 (`CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Mar 2019
- **Updated:** 20 Nov 2024
- **Also known as:** GHSA-c5vj-536j-jp5v

## What is CVE-2019-1756?

CVE-2019-1756 is a high-severity command injection vulnerability in Cisco Ios, published on 28 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A vulnerability in Cisco IOS XE Software could allow an authenticated, remote attacker to execute commands on the underlying Linux shell of an affected device with root privileges. The vulnerability occurs because the affected software improperly sanitizes user-supplied input. An attacker who has valid administrator access to an affected device could exploit this vulnerability by supplying a username with a malicious payload in the web UI and subsequently making a request to a specific endpoint in the web UI. A successful exploit could allow the attacker to run arbitrary commands as the root user, allowing complete compromise of the system.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2019-1756?

It affects 2 products.


Products: Cisco Ios, Cisco Ios Xe.

## How do I fix CVE-2019-1756?

No fix has been published for CVE-2019-1756 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1756 being exploited?

There is no known exploitation of CVE-2019-1756 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios

- [CVE-2017-12240](https://insights.sbomify.com/CVE-2017-12240/): Cisco IOS and IOS XE Software DHCP Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-3881](https://insights.sbomify.com/CVE-2017-3881/): Cisco IOS and IOS XE Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2018-0167](https://insights.sbomify.com/CVE-2018-0167/): Cisco IOS, XR, and XE Software Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2017-6736](https://insights.sbomify.com/CVE-2017-6736/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-6737](https://insights.sbomify.com/CVE-2017-6737/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1756 and fix it if it is affected.

What it is: CVE-2019-1756 is a high-severity command injection vulnerability in Cisco Ios, published on 28 Mar 2019. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-1756 in the wild and no public exploit code.

Affected product: Cisco Ios. 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-2019-1756/ (Markdown: https://insights.sbomify.com/CVE-2019-1756/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1756
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1756
- OSV: https://osv.dev/vulnerability/CVE-2019-1756

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-1756/
Summaries are generated and may contain mistakes; the official description above is the record.