CVE-2021-4477
Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass
CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th
Hirschmann HiLCOS OpenBAT and BAT450 products contain a firewall bypass vulnerability in IPv6 IPsec deployments that allows traffic from VPN connections to bypass configured firewall rules. Attackers can exploit this vulnerability by establishing IPv6 IPsec connections (IKEv1 or IKEv2) while simultaneously using an IPv6 Internet connection to circumvent firewall policy enforcement.
| CWE | CWE-284 |
| Vendor | belden |
| Product | hirschmann hilcos openbat |
| Published | Apr 3, 2026 |
| Last Updated | Apr 6, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None
Affected Versions
Belden / Hirschmann HiLCOS OpenBAT
3.80-REL 8.90-REL 9.00-REL 9.00-RU1 9.10-REL 9.12-REL 9.12-RU1 9.12-RU2 9.12-RU3 9.12-RU4 9.12-RU5 9.12-RU6 9.12-RU7 9.12-RU8 9.12-RU9 9.13-REL 9.13-RU1 10.12-REL 10.12-RU1