# CVE-2018-0170: Use after free in Cisco IOS XE

> An unauthenticated remote attacker can cause a denial of service on Cisco IOS XE devices by sending malformed packets that trigger a use-after-free error.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 28 Mar 2018
- **Updated:** 2 Dec 2024
- **Also known as:** GHSA-h5j7-h5xp-7395

## What is CVE-2018-0170?

CVE-2018-0170 is a high-severity use after free vulnerability in Cisco Ios Xe, published on 28 Mar 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the Cisco Umbrella Integration feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition, related to the OpenDNS software. The vulnerability is due to a logic error that exists when handling a malformed incoming packet, leading to access to an internal data structure after it has been freed. An attacker could exploit this vulnerability by sending crafted, malformed IP packets to an affected device. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvb86327.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2018-0170?

It affects 1 product.


Products: Cisco Ios Xe.

## How do I fix CVE-2018-0170?

No fix has been published for CVE-2018-0170 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-0170 being exploited?

There is no known exploitation of CVE-2018-0170 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-2018-0170 and fix it if it is affected.

What it is: CVE-2018-0170 is a high-severity use after free vulnerability in Cisco Ios Xe, published on 28 Mar 2018. 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-2018-0170 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-2018-0170/ (Markdown: https://insights.sbomify.com/CVE-2018-0170/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-0170
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-0170
- OSV: https://osv.dev/vulnerability/CVE-2018-0170

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-0170/
Summaries are generated and may contain mistakes; the official description above is the record.