CVE-2011-2059

Severity: medium (CVSS 5.0 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2011-10-22 · updated 2026-06-16
Weakness: CWE-200

Description

The ipv6 component in Cisco IOS before 15.1(4)M1.3 allows remote attackers to conduct fingerprinting attacks and obtain potentially sensitive information about the presence of the IOS operating system via an ICMPv6 Echo Request packet containing a Hop-by-Hop (HBH) extension header (EH) with a 0x0c01050c value in the PadN option data, aka Bug ID CSCtq02219.

Affected products

Cisco IOS: before 15.1\(4\)m1.3 — fixed in 15.1\(4\)m1.3

How to fix

Upgrade to a fixed version: Cisco IOS 15.1\(4\)m1.3. Check the vendor advisory for mitigations.

References

http://blogs.cisco.com/security/1999tcp-redux-the-ipv6-flavor
http://tools.cisco.com/security/center/viewIpsSignature.x?signatureId=36606&signatureSubId=0
http://blogs.cisco.com/security/1999tcp-redux-the-ipv6-flavor
http://tools.cisco.com/security/center/viewIpsSignature.x?signatureId=36606&signatureSubId=0

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