CVE-2021-36380 Sunhillo SureLine OS Command Injection Vulnerablity
Sunhillo SureLine contains an OS command injection vulnerability that allows an attacker to cause a denial-of-service or utilize the device for persistence on the network via shell metacharacters in ipAddr or dnsAddr in /cgi/networkDiag.cgi.
From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.
Should You Worry?
- CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 5 Mar 2024.
- Rated Critical severity (CVSS 9.8, scored by CISA).
- It has been in the catalogue for 976 days. Systems still unpatched now have almost certainly been scanned for it.
What It Is
Sunhillo SureLine before 8.7.0.1.1 allows Unauthenticated OS Command Injection via shell metacharacters in ipAddr or dnsAddr /cgi/networkDiag.cgi.
What To Do Now
- 1
Find it
Search your asset inventory and external attack surface for Sunhillo SureLine. Include cloud images, appliances and anything a supplier runs for you.
Attack Surface Management - 2
Fix it
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vulnerability Management - 3
Hunt for compromise
If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.
Incident Response - 4
Prove it is fixed
Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.
Penetration Testing
Vendor Advisories
The Compliance Clock
General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.
More Exploited Sunhillo Flaws
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