CVE-2026-89025 is a high severity web server dos flaw in Hirschmann HiOS, scored 7.5. Fixed in 07.1.12, 08.7.10, 09.0.13, 09.3.03, 10.3.08 and 10.5.00, per the record. Check your installed version against the affected list below, then patch or restrict access until you can. The record does not flag it as exploited.
What's affected
- Hirschmann HiOS Switch Platform devices with the integrated web server.
Severity in the record: High (7.5), vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Weakness: CWE-755.
Fix: Fixed in 07.1.12, 08.7.10, 09.0.13, 09.3.03, 10.3.08 and 10.5.00, per the record.
How to check if you're exposed
- Read the HiOS version in the device web interface or CLI system information.
- Match your release line to the fixed versions above.
Run these on every affected device, including ones in remote sites, labs and spares that are powered on.
What to do now
- Confirm the version of every affected system using the checks above.
- Read the vendor advisory linked in Sources and note the fixed version for your release line.
- Schedule the update, starting with systems that face untrusted networks or hold the most sensitive data.
- In the meantime: restrict web interface access to a management VLAN.
- Record the change, then recheck the version to confirm it took effect.
Why it matters
Missing validation of HTTP or HTTPS content in the web server (CWE-755, improper handling of exceptional conditions) lets a remote unauthenticated request to a specific endpoint cause an unintended reboot. The record calls the result a temporary denial of service. For industrial networks, even a reboot can interrupt traffic.
The record's KEV flag is false, so this post makes no claim that the flaw is exploited in the wild. That can change, so recheck the CISA catalog from time to time.
Network and management devices are patched less often than servers, because upgrades mean planned downtime. That gap is where a flaw like this stays open longest, so build the version check into your regular inventory.
The vector string in the record is a compact summary of how the flaw is reached and what it costs. AV is the attack vector (network, adjacent or local), PR is the privilege the attacker needs, and the C, I and A letters give the impact on confidentiality, integrity and availability. Read it against your own network layout rather than relying on the score alone.
After you patch
Patching is not the end of the job. Recheck the version on each system, because an upgrade that failed or rolled back looks the same as a success until someone looks. Keep the advisory link with your change record so the next reviewer can see why the update happened.
If you cannot patch soon, write down the reason, the compensating control you chose and a date to revisit. Exceptions without a date tend to become permanent.
Quick check
Which versions are fixed?
07.1.12, 08.7.10, 09.0.13, 09.3.03, 10.3.08 and 10.5.00, per the record.
Sources
-
Belden: PSIRT-6 advisory PDF
-
Safeguard Gold: CVE-2026-89025
Last reviewed: 18 October 2026.
