# CVE-2018-15372: Cisco IOS XE Software MACsec MKA Using EAP-TLS Authentication Bypass Vulnerability

> An unauthenticated adjacent attacker can bypass 802.1x network access controls and pass traffic through a Layer 3 interface on Cisco IOS XE devices configured for MACsec MKA with EAP-TLS.

- **Severity:** High 8.1 (`CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:** 5 Oct 2018
- **Updated:** 26 Nov 2024
- **Also known as:** GHSA-mv8q-r8fx-2m57

## What is CVE-2018-15372?

CVE-2018-15372 is a high-severity authentication bypass vulnerability in Cisco Ios Xe, published on 5 Oct 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A vulnerability in the MACsec Key Agreement (MKA) using Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) functionality of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to bypass authentication and pass traffic through a Layer 3 interface of an affected device. The vulnerability is due to a logic error in the affected software. An attacker could exploit this vulnerability by connecting to and passing traffic through a Layer 3 interface of an affected device, if the interface is configured for MACsec MKA using EAP-TLS and is running in access-session closed mode. A successful exploit could allow the attacker to bypass 802.1x network access controls and gain access to the network.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2018-15372?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2018-15372?

No fix has been published for CVE-2018-15372 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-15372 being exploited?

There is no known exploitation of CVE-2018-15372 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-2018-15372 and fix it if it is affected.

What it is: CVE-2018-15372 is a high-severity authentication bypass vulnerability in Cisco Ios Xe, published on 5 Oct 2018. 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-2018-15372 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-2018-15372/ (Markdown: https://insights.sbomify.com/CVE-2018-15372/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-15372
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-15372
- OSV: https://osv.dev/vulnerability/CVE-2018-15372

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-15372/
Summaries are generated and may contain mistakes; the official description above is the record.