CVE-2021-4477 Details
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.
A firewall bypass vulnerability has been identified in Hirschmann HiLCOS OpenBAT and BAT450 products, specifically in versions 8.80-REL prior to 10.12-RU2. This vulnerability occurs in IPv6 IPsec deployments, allowing traffic from VPN connections to circumvent established firewall rules. Exploitation involves creating IPv6 IPsec connections, either IKEv1 or IKEv2, while using an IPv6 Internet connection, thereby bypassing firewall policy enforcement.
Users are advised to update to version 10.12-RU2 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 6, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-284 | Improper Access Control | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 3, 2026 | New CVE Received | [email protected] |