# CVE-2020-3246: Cisco Umbrella Carriage Return Line Feed Injection Vulnerability

> An attacker can inject arbitrary HTTP headers into responses via a crafted URL, potentially bypassing security controls in Cisco Umbrella.

- **Severity:** Medium 4.7 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 6 May 2020
- **Updated:** 15 Nov 2024
- **Also known as:** GHSA-j53q-vx25-fmqm

## What is CVE-2020-3246?

CVE-2020-3246 is a medium-severity vulnerability in Cisco Umbrella, published on 6 May 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A vulnerability in the web server of Cisco Umbrella could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user of an affected service. The vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by persuading a user to access a crafted URL. A successful exploit could allow the attacker to inject arbitrary HTTP headers into valid HTTP responses sent to the browser of the user.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), CWE-93 (Improper Neutralization of CRLF Sequences)

## Which versions are affected by CVE-2020-3246?

It affects 1 product.


Products: Cisco Umbrella.

## How do I fix CVE-2020-3246?

No fix has been published for CVE-2020-3246 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-3246 being exploited?

There is no known exploitation of CVE-2020-3246 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Umbrella

- [CVE-2018-0435](https://insights.sbomify.com/CVE-2018-0435/): Cisco Umbrella API Unauthorized Access Vulnerability (critical 9.1)
- [CVE-2019-1807](https://insights.sbomify.com/CVE-2019-1807/): Cisco Umbrella Dashboard Session Management Vulnerability (high 7.6)
- [CVE-2021-1474](https://insights.sbomify.com/CVE-2021-1474/): Cisco Umbrella Link and CSV Formula Injection Vulnerabilities (medium 6.5)
- [CVE-2021-1475](https://insights.sbomify.com/CVE-2021-1475/): Cisco Umbrella Link and CSV Formula Injection Vulnerabilities (medium 6.5)
- [CVE-2019-1792](https://insights.sbomify.com/CVE-2019-1792/): Cisco Umbrella Cross-Site Scripting Vulnerability (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-3246 and fix it if it is affected.

What it is: CVE-2020-3246 is a medium-severity vulnerability in Cisco Umbrella, published on 6 May 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2020-3246 in the wild and no public exploit code.

Affected product: Cisco Umbrella. 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-2020-3246/ (Markdown: https://insights.sbomify.com/CVE-2020-3246/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-3246
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-3246
- OSV: https://osv.dev/vulnerability/CVE-2020-3246

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-3246/
Summaries are generated and may contain mistakes; the official description above is the record.