Medium severity · published Apr 3, 2026
CVE-2017-20233
Hirschmann HiLCOS Layer-2 Firewall Multicast Broadcast Traffic Bypass
5.4
CVSS
0.2%
EPSS
No
On KEV
Description
Hirschmann HiLCOS products OpenBAT, BAT450, WLC, BAT867 contains a firewall filtering vulnerability that fails to correctly filter IPv4 multicast and broadcast traffic when management IP address filtering is disabled, allowing configured filter rules to be bypassed. Attackers with network access can inject or observe multicast and broadcast packets that should have been blocked by the firewall.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
HH
Hirschmann HiLCOS BAT867 · Belden
through 9.14.5500-REL; 0 · source: vendor
HH
Hirschmann HiLCOS OpenBAT, BAT450, WLC · Belden
through 9.10.5126-REL; through 9.12.5500-REL · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2017-20233
CVE.org
https://www.cve.org/CVERecord?id=CVE-2017-20233
assets.belden.com
https://assets.belden.com/m/11a07596f0bf1018/original/Security-Bulletin-IPv4-Multicast-HiLCOS-Layer-2-Firewall-BSECV-2017-03.pdf
www.vulncheck.com
https://www.vulncheck.com/advisories/hirschmann-hilcos-layer-2-firewall-multicast-broadcast-traffic-bypass