Hirschmann HiLCOS OpenBAT BAT450 IPv6 IPsec Firewall Bypass

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2021-4477
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-03 23:17:01 UTC
Updated2026-04-03 23:17:01 UTC
DescriptionHirschmann 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.

Risk And Classification

Primary CVSS: v4.0 9.3 CRITICAL from [email protected]

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-284 | CWE-284 CWE-284 Improper access control

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.3CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS9.3CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
3.1[email protected]Primary9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNACVSS9.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Belden Hirschmann HiLCOS OpenBAT affected 3.80-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 8.90-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.00-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.00-RU1 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.10-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU1 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU2 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU3 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU4 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU5 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU6 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU7 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU8 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.12-RU9 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.13-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 9.13-RU1 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 10.12-REL custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT affected 10.12-RU1 custom Not specified
CNA Belden Hirschmann HiLCOS OpenBAT unaffected 10.12-RU2 custom Not specified

References

ReferenceSourceLinkTags
www.vulncheck.com/advisories/hirschmann-hilcos-openbat-bat450-ipv6-ipsec-firewa... [email protected] www.vulncheck.com
assets.belden.com/m/5fd1a50fa50cb252/original/Belden-Security-Bulletin-BSECV-1v... [email protected] assets.belden.com
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