# CVE-2017-12213: Auth bypass in Cisco Catalyst 4000 Series Switches

> An adjacent attacker can bypass 802.1x authentication on Cisco Catalyst switches, causing ports to fail open and allowing unauthorized traffic access.

- **Severity:** Medium 4.3 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **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:** 7 Sep 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-q9g3-ff96-6rfj

## What is CVE-2017-12213?

CVE-2017-12213 is a medium-severity authentication bypass vulnerability in Cisco Ios Xe, published on 7 Sep 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the dynamic access control list (ACL) feature of Cisco IOS XE Software running on Cisco Catalyst 4000 Series Switches could allow an unauthenticated, adjacent attacker to cause dynamic ACL assignment to fail and the port to fail open. This could allow the attacker to pass traffic to the default VLAN of the affected port. The vulnerability is due to an uncaught error condition that may occur during the reassignment of the auth-default-ACL dynamic ACL to a switch port after 802.1x authentication fails. A successful exploit of this issue could allow a physically adjacent attacker to bypass 802.1x authentication and cause the affected port to fail open, allowing the attacker to pass traffic to the default VLAN of the affected switch port. Cisco Bug IDs: CSCvc72751.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2017-12213?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2017-12213?

No fix has been published for CVE-2017-12213 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-12213 being exploited?

There is no known exploitation of CVE-2017-12213 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios Xe

- [CVE-2023-20198](https://insights.sbomify.com/CVE-2023-20198/): Cisco IOS XE Web UI Privilege Escalation (critical 10.0, exploited in the wild)
- [CVE-2018-0151](https://insights.sbomify.com/CVE-2018-0151/): Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2023-20273](https://insights.sbomify.com/CVE-2023-20273/): Cisco IOS XE Web UI Command Injection (high 7.2, exploited in the wild)
- [CVE-2025-20188](https://insights.sbomify.com/CVE-2025-20188/): Hardcoded credentials in Cisco IOS XE Software (critical 10.0)
- [CVE-2021-34770](https://insights.sbomify.com/CVE-2021-34770/): Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability (critical 10.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-12213 and fix it if it is affected.

What it is: CVE-2017-12213 is a medium-severity authentication bypass vulnerability in Cisco Ios Xe, published on 7 Sep 2017. 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-2017-12213 in the wild and no public exploit code.

Affected product: Cisco Ios Xe. 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-2017-12213/ (Markdown: https://insights.sbomify.com/CVE-2017-12213/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-12213
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-12213
- OSV: https://osv.dev/vulnerability/CVE-2017-12213

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-12213/
Summaries are generated and may contain mistakes; the official description above is the record.