Internet Key Exchange (IKE) version 1 protocol, as implemented on Cisco IOS, VPN 3000 Concentrators, and PIX firewalls, allows remote attackers to cause a denial of service (resource exhaustion) via a flood of IKE Phase-1 packets that exceed the session expiration rate. NOTE: it has been argued that this is due to a design weakness of the IKE version 1 protocol, in which case other vendors and implementations would also be affected.
Conclusion & alert: CVE-2006-3906 is rated Moderate Risk (49/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.13%). 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 | 4.28% | 3.13% | -1.15% |
| 2 | 2025-12-28 | 3.68% | 4.28% | +0.60% |
| 3 | 2025-12-27 | — | 3.68% | — |
Full EPSS history (15 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2006-3906: no source package rows; 0 state rows across 0 repos (none); fixed 0, open 0. | https://security.alpinelinux.org/vuln/CVE-2006-3906 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| cisco | ios | — | cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:* |
| cisco | vpn_3001_concentrator | — | cpe:2.3:h:cisco:vpn_3001_concentrator:*:*:*:*:*:*:*:* |
| cisco | vpn_3015_concentrator | — | cpe:2.3:h:cisco:vpn_3015_concentrator:*:*:*:*:*:*:*:* |
| cisco | vpn_3020_concentrator | — | cpe:2.3:h:cisco:vpn_3020_concentrator:*:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | — | cpe:2.3:h:cisco:vpn_3030_concentator:*:*:*:*:*:*:*:* |
| cisco | vpn_3060_concentrator | — | cpe:2.3:h:cisco:vpn_3060_concentrator:*:*:*:*:*:*:*:* |
| cisco | vpn_3080_concentrator | — | cpe:2.3:h:cisco:vpn_3080_concentrator:*:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.0 | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.0:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.0\(4\) | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.0\(4\):*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.0\(5\) | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.0\(5\):*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.0.1.4 | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.0.1.4:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.0.4.3 | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.0.4.3:*:*:*:*:*:*:* |
| cisco | adaptive_security_appliance_software | 7.1\(2\) | cpe:2.3:o:cisco:adaptive_security_appliance_software:7.1\(2\):*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.0 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.0:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.5.2.a | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.5.2.a:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.5.2.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.5.2.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.5.2.c | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.5.2.c:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.5.2.d | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.5.2.d:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 2.5.2.f | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:2.5.2.f:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.0 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.0:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.0.3.a | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.0.3.a:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.0.3.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.0.3.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.0.4 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.0.4:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.1\(rel\) | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.1\(rel\):*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.1.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.1.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.1.2 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.1.2:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.1.4 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.1.4:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5\(rel\) | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5\(rel\):*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5.2 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5.2:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5.3 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5.3:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5.4 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5.4:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.5.5 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.5.5:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.3 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.3:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.5 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.5:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7.a | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7.a:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7.c | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7.c:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7.d | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7.d:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7.f | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7.f:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 3.6.7d | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:3.6.7d:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.0 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.0:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.0.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.0.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.0.2 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.0.2:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.0.5.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.0.5.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.1.5.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.1.5.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.1.7.a | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.1.7.a:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.1.7.b | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.1.7.b:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.1.7.l | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.1.7.l:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7\(rel\) | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7\(rel\):*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7.1 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7.1:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7.1.f | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7.1.f:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7.2 | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7.2:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7.2.a | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7.2.a:*:*:*:*:*:*:* |
| cisco | vpn_3000_concentrator_series_software | 4.7.2.f | cpe:2.3:o:cisco:vpn_3000_concentrator_series_software:4.7.2.f:*:*:*:*:*:*:* |
| cisco | vpn_3005_concentrator_software | 4.0.1 | cpe:2.3:o:cisco:vpn_3005_concentrator_software:4.0.1:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7\(rel\) | cpe:2.3:o:cisco:vpn_3030_concentator:4.7\(rel\):*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7.1 | cpe:2.3:o:cisco:vpn_3030_concentator:4.7.1:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7.1.f | cpe:2.3:o:cisco:vpn_3030_concentator:4.7.1.f:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7.2 | cpe:2.3:o:cisco:vpn_3030_concentator:4.7.2:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7.2.a | cpe:2.3:o:cisco:vpn_3030_concentator:4.7.2.a:*:*:*:*:*:*:* |
| cisco | vpn_3030_concentator | 4.7.2.f | cpe:2.3:o:cisco:vpn_3030_concentator:4.7.2.f:*:*:*:*:*:*:* |
| cisco | pix_asa_ids | — | cpe:2.3:a:cisco:pix_asa_ids:*:*:*:*:*:*:*:* |
| cisco | pix_firewall | 6.2.2_.111 | cpe:2.3:a:cisco:pix_firewall:6.2.2_.111:*:*:*:*:*:*:* |
| cisco | pix_firewall | 6.2.3_\(110\) | cpe:2.3:a:cisco:pix_firewall:6.2.3_\(110\):*:*:*:*:*:*:* |
| cisco | pix_firewall | 6.3.3_\(133\) | cpe:2.3:a:cisco:pix_firewall:6.3.3_\(133\):*:*:*:*:*:*:* |
| cisco | pix_firewall | 6.3.5_\(112\) | cpe:2.3:a:cisco:pix_firewall:6.3.5_\(112\):*:*:*:*:*:*:* |
| cisco | pix_firewall_501 | — | cpe:2.3:h:cisco:pix_firewall_501:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_506 | — | cpe:2.3:h:cisco:pix_firewall_506:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_515 | — | cpe:2.3:h:cisco:pix_firewall_515:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_515e | — | cpe:2.3:h:cisco:pix_firewall_515e:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_520 | — | cpe:2.3:h:cisco:pix_firewall_520:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_525 | — | cpe:2.3:h:cisco:pix_firewall_525:*:*:*:*:*:*:*:* |
| cisco | pix_firewall_535 | — | cpe:2.3:h:cisco:pix_firewall_535:*:*:*:*:*:*:*:* |