# CVE-2026-22781: TinyWeb CGI Command Injection

> An unauthenticated remote attacker can execute arbitrary commands on TinyWeb HTTP Server by injecting shell metacharacters into CGI query parameters.

- **Severity:** Critical 10.0 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Jan 2026
- **Updated:** 12 Jan 2026
- **Also known as:** GHSA-m779-84h5-72q2

## What is CVE-2026-22781?

CVE-2026-22781 is a critical command injection vulnerability in maximmasiutin TinyWeb, published on 12 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. TinyWeb HTTP Server before version 1.98 is vulnerable to OS command injection via CGI ISINDEX-style query parameters. The query parameters are passed as command-line arguments to the CGI executable via Windows CreateProcess(). An unauthenticated remote attacker can execute arbitrary commands on the server by injecting Windows shell metacharacters into HTTP requests. This vulnerability is fixed in 1.98.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-22781?

It affects 1 product.


Products: Ritlabs Tinyweb.

## How do I fix CVE-2026-22781?

No fix has been published for CVE-2026-22781 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-22781 being exploited?

There is no known exploitation of CVE-2026-22781 in the wild and no public exploit code.

## Other vulnerabilities in maximmasiutin TinyWeb

- [CVE-2026-27613](https://insights.sbomify.com/CVE-2026-27613/): CGI Parameter Injection (Bypass of STRICT_CGI_PARAMS and EscapeShellParam) (critical 10.0)
- [CVE-2026-28497](https://insights.sbomify.com/CVE-2026-28497/): TinyWeb: Integer Overflow in `_Val` (HTTP Request Smuggling) (critical 9.3)
- [CVE-2026-29046](https://insights.sbomify.com/CVE-2026-29046/): TinyWeb: HTTP Header Control Character Injection into CGI Environment (critical 9.2)
- [CVE-2026-27630](https://insights.sbomify.com/CVE-2026-27630/): TinyWeb vulnerable to Remote Denial of Service via Thread/Connection Exhaustion (Slowloris) (high 8.7)
- [CVE-2026-27633](https://insights.sbomify.com/CVE-2026-27633/): TinyWeb has Unbounded Content-Length Memory Exhaustion (DoS) (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22781 and fix it if it is affected.

What it is: CVE-2026-22781 is a critical command injection vulnerability in maximmasiutin TinyWeb, published on 12 Jan 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-2026-22781 in the wild and no public exploit code.

Affected product: maximmasiutin TinyWeb. 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-2026-22781/ (Markdown: https://insights.sbomify.com/CVE-2026-22781/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22781
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22781
- OSV: https://osv.dev/vulnerability/CVE-2026-22781

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22781/
Summaries are generated and may contain mistakes; the official description above is the record.