CVE-2021-4477

CRITICAL

Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass

Title source: cna
STIX 2.1

Description

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.

References (2)

Core 2

Scores

CVSS v3 9.1
EPSS 0.0032
EPSS Percentile 23.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact total

Details

CWE
CWE-284
Status published
Products (20)
Belden/Hirschmann HiLCOS OpenBAT 10.12-REL
Belden/Hirschmann HiLCOS OpenBAT 10.12-RU1
Belden/Hirschmann HiLCOS OpenBAT 10.12-RU2
Belden/Hirschmann HiLCOS OpenBAT 3.80-REL
Belden/Hirschmann HiLCOS OpenBAT 8.90-REL
Belden/Hirschmann HiLCOS OpenBAT 9.00-REL
Belden/Hirschmann HiLCOS OpenBAT 9.00-RU1
Belden/Hirschmann HiLCOS OpenBAT 9.10-REL
Belden/Hirschmann HiLCOS OpenBAT 9.12-REL
Belden/Hirschmann HiLCOS OpenBAT 9.12-RU1
... and 10 more
Published Apr 03, 2026
Tracked Since Apr 04, 2026