Belden Hirschmann HiLCOS OpenBAT up to 10.12-RU1 Policy Enforcement access control

CVSS Meta Temp Score
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CTI Interest Score
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8.0$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, was found in Belden Hirschmann HiLCOS OpenBAT. The impacted element is an unknown function of the component Policy Enforcement Handler. Executing a manipulation can lead to access control. This vulnerability is tracked as CVE-2021-4477. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in Belden Hirschmann HiLCOS OpenBAT and classified as critical. This vulnerability affects some unknown functionality of the component Policy Enforcement Handler. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at assets.belden.com. This vulnerability was named CVE-2021-4477 since 04/03/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1068.

Upgrading to version 10.12-RU2 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 9.1
CNA Vector (VulnCheck): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Hirschmann HiLCOS OpenBAT 10.12-RU2

Timelineinfo

04/03/2026 CVE reserved
04/04/2026 +1 days Advisory disclosed
04/04/2026 +0 days VulDB entry created
04/04/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: assets.belden.com
Status: Confirmed

CVE: CVE-2021-4477 (🔒)
GCVE (CVE): GCVE-0-2021-4477
GCVE (VulDB): GCVE-100-355252

Entryinfo

Created: 04/04/2026 07:40
Changes: 04/04/2026 07:40 (76)
Complete: 🔍
Cache ID: 216:F12:103

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