CVE-2021-4477 in Hirschmann HiLCOS OpenBAT
Summary
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.
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Responsible
VulnCheck
Reservation
04/03/2026
Disclosure
04/04/2026
Status
Confirmed
Entries
VulDB provides additional information and datapoints for this CVE:
| ID | Vulnerability | CWE | Exp | Cou | CVE |
|---|---|---|---|---|---|
| 355252 | Belden Hirschmann HiLCOS OpenBAT Policy Enforcement access control | 284 | Not defined | Official fix | CVE-2021-4477 |