cvedb.io
CVE-2021-4477
CRITICAL · CVSS 9.1
EPSS exploitation probability: 0%
Published 2026-04-03T23:17:01.043 · Last modified 2026-07-24T22:10:00.140

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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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.