Unspecified vulnerability in the VLAN Trunking Protocol (VTP) implementation on Cisco IOS and CatOS, when the VTP operating mode is not transparent, allows remote attackers to cause a denial of service (device reload or hang) via a crafted VTP packet sent to a switch interface configured as a trunk port.
Conclusion & alert: CVE-2008-4963 is rated Moderate Risk (55/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.68%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.91% | 1.68% | +0.77% |
| 2 | 2025-12-28 | 1.03% | 0.91% | -0.12% |
| 3 | 2025-12-27 | — | 1.03% | — |
Full EPSS history (15 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.1 | 2.0 | HIGH |
|
8.6 | 6.9 | [email protected] |