CVE-2005-4440

CVE-2005-4440 is a medium-severity vulnerability in Vlan Protocol with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

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."

Frequently asked questions

What is CVE-2005-4440?
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."
How severe is CVE-2005-4440?
CVE-2005-4440 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2005-4440 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2005-4440?
CVE-2005-4440 affects Vlan Protocol. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2005-4440?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2005-4440 published?
CVE-2005-4440 was published on 2005-12-21 and last updated on 2026-06-16.

References

Affected products (1)