RCE in Maximmasiutin Tinyweb
CVE-2026-22781
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.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.024 (84.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 84.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.025 · newest: 0.024 · change: -0.000
Affected products
- Maximmasiutin Tinyweb — versions < 1.98
- Ritlabs Tinyweb
Weakness classification (CWE)
References
- github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-m779-84h5-72q2 (Third Party Advisory)
- github.com/maximmasiutin/TinyWeb/commit/876b7e2887f4ea5be3e18bb2af7313f23a283c96 (Patch)
- www.masiutin.net/tinyweb-cve-2025-cgi-command-injection.html (Third Party Advisory)
Frequently asked questions
- What is CVE-2026-22781?
- CVE-2026-22781 is a critical-severity vulnerability in Maximmasiutin Tinyweb, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-01-12.
- How severe is CVE-2026-22781?
- Critical severity. CVSS v3 base score is 9.8 out of 10.