# CVE-2017-3827: Security feature bypass in Cisco AsyncOS Software for Cisco ESA and Cisco WSA

> Remote attackers can bypass configured user filters on Cisco Email and Web Security Appliances by exploiting a MIME scanner vulnerability.

- **Severity:** Medium 5.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 22 Feb 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-mr7q-8c5m-vw8x

## What is CVE-2017-3827?

CVE-2017-3827 is a medium-severity vulnerability in Cisco Web Security Appliance, published on 22 Feb 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) and Web Security Appliances (WSA) could allow an unauthenticated, remote attacker to bypass configured user filters on the device. Affected Products: This vulnerability affects all releases prior to the first fixed release of Cisco AsyncOS Software for Cisco ESA and Cisco WSA, both virtual and hardware appliances, that are configured with message or content filters to scan incoming email attachments on the ESA or services scanning content of web access on the WSA. More Information: SCvb91473, CSCvc76500. Known Affected Releases: 10.0.0-203 9.9.9-894 WSA10.0.0-233.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2017-3827?

It affects 2 products.


Products: Cisco Email Security Appliance Firmware, Cisco Web Security Appliance.

## How do I fix CVE-2017-3827?

No fix has been published for CVE-2017-3827 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-3827 being exploited?

There is no known exploitation of CVE-2017-3827 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Web Security Appliance

- [CVE-2016-6406](https://insights.sbomify.com/CVE-2016-6406/): Auth bypass in n/a (critical 9.8)
- [CVE-2018-15453](https://insights.sbomify.com/CVE-2018-15453/): Cisco Email Security Appliance Memory Corruption Denial of Service Vulnerability (high 8.6)
- [CVE-2017-6671](https://insights.sbomify.com/CVE-2017-6671/): Security feature bypass in Cisco Email Security Appliance (high 7.5)
- [CVE-2016-6458](https://insights.sbomify.com/CVE-2016-6458/): Security feature bypass in Cisco AsyncOS 10.0.0-125 and 9.7.1-066 (high 7.5)
- [CVE-2019-12706](https://insights.sbomify.com/CVE-2019-12706/): Cisco Email Security Appliance Filter Bypass Vulnerability (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-3827 and fix it if it is affected.

What it is: CVE-2017-3827 is a medium-severity vulnerability in Cisco Web Security Appliance, published on 22 Feb 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-3827 in the wild and no public exploit code.

Affected product: Cisco Web Security Appliance. 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-2017-3827/ (Markdown: https://insights.sbomify.com/CVE-2017-3827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-3827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-3827
- OSV: https://osv.dev/vulnerability/CVE-2017-3827

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-3827/
Summaries are generated and may contain mistakes; the official description above is the record.