CVE-2021-4477

Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass

CVSS 9.3 CRITICALEPSS 0.3%CWE-284

Vexday Risk Score

28Bajo

Decisión SSVC (CISA)

Track

Sin señal de explotación → monitorear

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

Ciclo de vida

03 abr 2026Publicada en NVD

Recomendación: Monitorear — sin señal de explotación por ahora.

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

Productos afectados

Belden · Hirschmann HiLCOS OpenBAT

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Referencias

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