CVE-2021-4477

Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass

CVSS 9.3 CRITICALEPSS 0.3%CWE-284

Vexday Risk Score

28Baixo

Decisão SSVC (CISA)

Track

Sem sinal de exploração → monitorar

CVSS 9.3EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch referenciado

Ciclo de vida

03 abr 2026Publicada no NVD

Recomendação: Monitorar — sem sinal de exploração no momento.

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.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Produtos afetados

Belden · Hirschmann HiLCOS OpenBAT

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Referências

https://assets.belden.com/m/5fd1a50fa50cb252/original/Belden-Security-Bulletin-BSECV-1v0-2019-09.pdf https://www.vulncheck.com/advisories/hirschmann-hilcos-openbat-bat450-ipv6-ipsec-firewall-bypass