CVE-2026-12200: Ritlabs TinyWeb Server Header libeay32.dll.html stack-based overflow
A security vulnerability has been detected in Ritlabs TinyWeb Server up to 1.94 on Win32. This impacts an unknown function in the library libeay32.dll.html of the component Header Handler. The manipulation of the argument Authorization leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Remove
Remove
Ritlabs TinyWeb Serverfrom your environment.Uninstall or stop the Ritlabs TinyWeb Server on any affected Windows (Win32) systems if the service is not required. Remove the associated Header Handler component (libeay32.dll.html) or the entire product to eliminate the vulnerable code.
- Compensating control
Restrict network access to hosts running the TinyWeb Server using firewall rules or ACLs to allow only trusted management IPs. Deploy a WAF or edge filter to block or drop HTTP requests containing an Authorization header to prevent triggering the vulnerable Header Handler.
- Operational
Isolate and take offline any systems known to run the affected server until remediation is implemented. Review web server logs and intrusion detection alerts for exploitation attempts (noting public exploit availability) and preserve forensic evidence for affected hosts.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-12200?
The severity of CVE-2026-12200 is rated as high with a score of 7.3.
What is CVE-2026-12200?
CVE-2026-12200 is a stack-based buffer overflow vulnerability in the Header Handler component of Ritlabs TinyWeb Server due to the manipulation of the Authorization argument.
How do I fix CVE-2026-12200?
To fix CVE-2026-12200, upgrade to the latest version of Ritlabs TinyWeb Server that addresses the buffer overflow vulnerability.
What systems are affected by CVE-2026-12200?
CVE-2026-12200 affects Ritlabs TinyWeb Server versions up to and including 1.94 on Win32 systems.
What is the potential impact of exploiting CVE-2026-12200?
Exploiting CVE-2026-12200 can lead to stack-based overflow, potentially allowing an attacker to execute arbitrary code.