# CVE-2018-15369: Cisco IOS and IOS XE Software TACACS+ Client Denial of Service Vulnerability

> An unauthenticated remote attacker can cause a Cisco IOS device to reload by injecting crafted TACACS+ packets, resulting in a denial of service.

- **Severity:** Medium 6.8 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/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:** 5 Oct 2018
- **Updated:** 26 Nov 2024
- **Also known as:** GHSA-cfgw-ch55-2g87

## What is CVE-2018-15369?

CVE-2018-15369 is a medium-severity denial of service vulnerability in Cisco Ios, published on 5 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the TACACS+ client subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of crafted TACACS+ response packets by the affected software. An attacker could exploit this vulnerability by injecting a crafted TACACS+ packet into an existing TACACS+ session between an affected device and a TACACS+ server or by impersonating a known, valid TACACS+ server and sending a crafted TACACS+ packet to an affected device when establishing a connection to the device. To exploit this vulnerability by using either method, the attacker must know the shared TACACS+ secret and the crafted packet must be sent in response to a TACACS+ request from a TACACS+ client. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2018-15369?

It affects 2 products.


Products: Cisco Ios, Cisco Ios Xe.

## How do I fix CVE-2018-15369?

No fix has been published for CVE-2018-15369 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-15369 being exploited?

There is no known exploitation of CVE-2018-15369 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Ios

- [CVE-2017-12240](https://insights.sbomify.com/CVE-2017-12240/): Cisco IOS and IOS XE Software DHCP Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2017-3881](https://insights.sbomify.com/CVE-2017-3881/): Cisco IOS and IOS XE Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2018-0167](https://insights.sbomify.com/CVE-2018-0167/): Cisco IOS, XR, and XE Software Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2017-6736](https://insights.sbomify.com/CVE-2017-6736/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)
- [CVE-2017-6737](https://insights.sbomify.com/CVE-2017-6737/): Cisco IOS and IOS XE Software SNMP Remote Code Execution (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-15369 and fix it if it is affected.

What it is: CVE-2018-15369 is a medium-severity denial of service vulnerability in Cisco Ios, published on 5 Oct 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-2018-15369 in the wild and no public exploit code.

Affected product: Cisco Ios. 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-2018-15369/ (Markdown: https://insights.sbomify.com/CVE-2018-15369/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-15369
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-15369
- OSV: https://osv.dev/vulnerability/CVE-2018-15369

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From sbomify Insights: https://insights.sbomify.com/CVE-2018-15369/
Summaries are generated and may contain mistakes; the official description above is the record.