# CVE-2026-12200: Ritlabs TinyWeb Server Header libeay32.dll.html stack-based overflow

> Remote attackers can trigger a stack-based buffer overflow in Ritlabs TinyWeb Server via the Authorization header, potentially leading to code execution or service disruption.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Jun 2026
- **Updated:** 15 Jun 2026
- **Also known as:** GHSA-gpg8-377c-3rgp

## What is CVE-2026-12200?

CVE-2026-12200 is a medium-severity memory corruption vulnerability in Ritlabs TinyWeb Server, published on 15 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-121 (Stack-based Buffer Overflow), CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-12200?


## How do I fix CVE-2026-12200?

No fix has been published for CVE-2026-12200 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12200 being exploited?

There is no known exploitation of CVE-2026-12200 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12200 and fix it if it is affected.

What it is: CVE-2026-12200 is a medium-severity memory corruption vulnerability in Ritlabs TinyWeb Server, published on 15 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-12200 in the wild and no public exploit code.

Affected product: Ritlabs TinyWeb Server. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12200/ (Markdown: https://insights.sbomify.com/CVE-2026-12200/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12200
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12200
- OSV: https://osv.dev/vulnerability/CVE-2026-12200

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12200/
Summaries are generated and may contain mistakes; the official description above is the record.