CVE-2026-27613
CGI Parameter Injection (Bypass of STRICT_CGI_PARAMS and EscapeShellParam)
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure STRICT_CGI_PARAMS is enabled (it is defined by default in define.inc) and/or do not use CGI executables that natively accept dangerous command-line flags (such as php-cgi.exe). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (-) or contain encoded double quotes (%22).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
10.0
CGI Parameter Injection (Bypass of STRICT_CGI_PARAMS and EscapeShellParam)
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure STRICT_CGI_PARAMS is enabled (it is defined by default in define.inc) and/or do not use CGI executables that natively accept dangerous command-line flags (such as php-cgi.exe). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (-) or contain encoded double quotes (%22).
- Record
CVE-2026-27613- CVSS 4.0
- 10.0 Critical
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 - Weakness
- CWE-78, CWE-88
- Updated
- 2026-11-02
EUVDEUVD-2026-8763
10.0
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure STRICT_CGI_PARAMS is enabled (it is defined by default in define.inc) and/or do not use CGI executables that natively accept dangerous command-line flags (such as php-cgi.exe). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (-) or contain encoded double quotes (%22).
- Record
EUVD-2026-8763- CVSS 4.0
- 10.0 Critical
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 - Updated
- 2026-11-02
NVD
10.0
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure STRICT_CGI_PARAMS is enabled (it is defined by default in define.inc) and/or do not use CGI executables that natively accept dangerous command-line flags (such as php-cgi.exe). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (-) or contain encoded double quotes (%22).
- Record
CVE-2026-27613- CVSS 4.0
- 10.0 Critical
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-78, CWE-88
- Updated
- 2026-11-02
OSV
10.0
CGI Parameter Injection (Bypass of STRICT_CGI_PARAMS and EscapeShellParam)
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. A vulnerability in versions prior to 2.01 allows unauthenticated remote attackers to bypass the web server's CGI parameter security controls. Depending on the server configuration and the specific CGI executable in use, the impact is either source code disclosure or remote code execution (RCE). Anyone hosting CGI scripts (particularly interpreted languages like PHP) using vulnerable versions of TinyWeb is impacted. The problem has been patched in version 2.01. If upgrading is not immediately possible, ensure STRICT_CGI_PARAMS is enabled (it is defined by default in define.inc) and/or do not use CGI executables that natively accept dangerous command-line flags (such as php-cgi.exe). If hosting PHP, consider placing the server behind a Web Application Firewall (WAF) that explicitly blocks URL query string parameters that begin with a hyphen (-) or contain encoded double quotes (%22).
- Record
CVE-2026-27613- CVSS 4.0
- 10.0 Critical
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 - Weakness
- CWE-78, CWE-88
- Updated
- 2026-11-05
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-27613 is a critical vulnerability (CVSS 10.0) in Maximmasiutin Tinyweb, published February 25, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.87%, the 59th percentile. No source names a fixed version.
References
github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-rfx5-fh9m-9jj9
github.com/maximmasiutin/TinyWeb/commit/d9dbda8db49da69d2160e1c527e782b73b5ffb6b
github.com/maximmasiutin/TinyWeb/releases/tag/v2.01
masiutin.net/tinyweb-cve-2026-27613.html
github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27613.json
nvd.nist.gov/vuln/detail/CVE-2026-27613