CVE-2005-4440

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: 2005-12-21 · updated 2026-06-16

Description

The 802.1q VLAN protocol allows remote attackers to bypass network segmentation and spoof VLAN traffic via a message with two 802.1q tags, which causes the second tag to be redirected from a downstream switch after the first tag has been stripped, as demonstrated by Yersinia, aka "double-tagging VLAN jumping attack."

Affected products

Vlan Protocol: 802.1q

References

http://lists.grok.org.uk/pipermail/full-disclosure/2005-December/040333.html
http://www.securityfocus.com/archive/1/419831/100/0/threaded
http://www.securityfocus.com/archive/1/419834/100/0/threaded
http://lists.grok.org.uk/pipermail/full-disclosure/2005-December/040333.html
http://www.securityfocus.com/archive/1/419831/100/0/threaded
http://www.securityfocus.com/archive/1/419834/100/0/threaded

Get alerted when CVE-2005-4440 or the next vulnerability affects your stack