CVE-2026-12200
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceStack-based buffer overflow in Ritlabs TinyWeb Server's Header Handler when processing the Authorization header argument. The vulnerability exists in libeay32.dll.html and allows remote attackers to potentially execute arbitrary code via overly long Authorization credentials.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Ritlabs TinyWeb Server is installedCheck the system for TinyWeb Server by looking for the executable (tinyweb.exe) in common installation directories such as C:\Program Files\TinyWeb or C:\TinyWeb, or search for the process running on common HTTP ports (80, 8080)Affected if TinyWeb Server executable is found running or installed on the system
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Identify the installed versionRight-click on tinyweb.exe, select Properties, and check the File Version field under the Details tab. Alternatively, check any version.txt or README file in the installation directoryAffected if The version number is 1.94 or lower (the summary states versions up to v1.94 are affected)
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Verify the vulnerable component existsCheck for the presence of libeay32.dll.html in the TinyWeb installation directory - this is the Header Handler component cited in the vulnerabilityAffected if libeay32.dll.html exists in the TinyWeb installation folder
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Determine network exposureCheck if TinyWeb Server is bound to a network-accessible IP address or is listening on interfaces exposed to untrusted networks. Review the server configuration for allowed clients or IP restrictionsAffected if The server is listening on a public or untrusted network interface and accepts incoming HTTP requests containing the Authorization header
You are affected if Ritlabs TinyWeb Server v1.94 or lower is installed, the libeay32.dll.html component is present, and the server is network-accessible to handle malicious Authorization headers.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement strict bounds checking on the Authorization header input in the Header Handler component. Consider upgrading to a patched version once available or implementing input validation/limiting at the web server level.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-12200 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-12200 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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