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CVE-2021-4477— Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass

Quick assessment

Affected
Belden Hirschmann HiLCOS OpenBAT
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Belden Hirschmann HiLCOS OpenBAT是美国Belden公司的一款工业级无线局域网设备。 Belden Hirschmann HiLCOS OpenBAT存在访问控制错误漏洞，该漏洞源于IPv6 IPsec部署中的防火墙绕过问题，可能导致VPN连接流量绕过配置的防火墙规则。

CVSS 9.1 · Critical EPSS 0.32% · P23
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I. Basic Information for CVE-2021-4477

Vulnerability Information
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Vulnerability Title
Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
访问控制不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Belden Hirschmann HiLCOS OpenBAT 访问控制错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Belden Hirschmann HiLCOS OpenBAT是美国Belden公司的一款工业级无线局域网设备。 Belden Hirschmann HiLCOS OpenBAT存在访问控制错误漏洞，该漏洞源于IPv6 IPsec部署中的防火墙绕过问题，可能导致VPN连接流量绕过配置的防火墙规则。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

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Affected Products

Vendor Product Affected Versions CPE Subscribe
Belden Hirschmann HiLCOS OpenBAT 3.80-REL -

II. Public POCs for CVE-2021-4477

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III. Intelligence Information for CVE-2021-4477

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Vendor Advisories for CVE-2021-4477 (1)

Same Patch Batch · Belden · 2026-04-03 · 11 CVEs total

CVE-2017-20237 9.8 CRITICAL Hirschmann Industrial HiVision Authentication Bypass Remote Code Execution
CVE-2018-25237 9.8 CRITICAL Hirschmann HiSecOS Buffer Overflow via HTTPS Login
CVE-2018-25236 9.8 CRITICAL Hirschmann HiOS HiSecOS Authentication Bypass via HTTP Management
CVE-2017-20234 9.8 CRITICAL GarrettCom Magnum 6K and 10K Authentication Bypass via Hardcoded String
CVE-2015-10148 8.2 HIGH Hirschmann HiLCOS Hard-coded Credentials SSH SSL Keys
CVE-2016-15058 8.1 HIGH Hirschmann HiLCOS Classic Platform Password Exposure via SNMP
CVE-2020-37216 7.5 HIGH Hirschmann HiOS EtherNet/IP Stack Denial of Service
CVE-2022-4987 7.3 HIGH Hirschmann Industrial HiVision External Application Path Hijacking Leading to Arbitrary Co
CVE-2017-20238 7.1 HIGH Hirschmann Industrial HiVision Improper Authorization Privilege Escalation
CVE-2017-20233 5.4 MEDIUM Hirschmann HiLCOS Layer-2 Firewall Multicast Broadcast Traffic Bypass

IV. Related Vulnerabilities

Same vendor: Belden
Same weakness: CWE-284

V. Comments for CVE-2021-4477

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