CVE-2010-4671

Severity: high (CVSS 7.8 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2011-01-07 · updated 2026-06-16
Weakness: CWE-400

Description

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS before 15.0(1)XA5 allows remote attackers to cause a denial of service (CPU consumption and device hang) by sending many Router Advertisement (RA) messages with different source addresses, as demonstrated by the flood_router6 program in the thc-ipv6 package, aka Bug ID CSCti33534.

Affected products

Cisco IOS: before 15.0\(1\)xa5 — fixed in 15.0\(1\)xa5

How to fix

Upgrade to a fixed version: Cisco IOS 15.0\(1\)xa5. Check the vendor advisory for mitigations.

References

http://events.ccc.de/congress/2010/Fahrplan/events/3957.en.html
http://mirror.fem-net.de/CCC/27C3/mp3-audio-only/27c3-3957-en-ipv6_insecurities.mp3
http://mirror.fem-net.de/CCC/27C3/mp4-h264-HQ/27c3-3957-en-ipv6_insecurities.mp4
http://www.ciscosystems.com/en/US/docs/ios/15_0/15_0x/15_01_XA/rn800xa.pdf
http://www.securityfocus.com/bid/45760
http://www.youtube.com/watch?v=00yjWB6gGy8
https://exchange.xforce.ibmcloud.com/vulnerabilities/64589
http://events.ccc.de/congress/2010/Fahrplan/events/3957.en.html
http://mirror.fem-net.de/CCC/27C3/mp3-audio-only/27c3-3957-en-ipv6_insecurities.mp3
http://mirror.fem-net.de/CCC/27C3/mp4-h264-HQ/27c3-3957-en-ipv6_insecurities.mp4
http://www.ciscosystems.com/en/US/docs/ios/15_0/15_0x/15_01_XA/rn800xa.pdf
http://www.securityfocus.com/bid/45760

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