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TI-2026-21999 Aliases CVE-2026-27613

CGI Parameter Injection (Bypass of STRICT_CGI_PARAMS and EscapeShellParam)

Priority MEDIUM 50CWE-78Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-78.

Summary

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`).

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00869 59th percentileScored 2026-11-07
Fix Fixed TinyWeb (maximmasiutin): 2.01

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
maximmasiutinTinyWebbefore 2.012.01Patch availableCNA
  • TinyWeb Vendormaximmasiutin Affected before 2.01 Fixed in 2.01 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:ritlabs:tinyweb:*:*:*:*:*:*:*:*before 2.01Vulnerablemaximmasiutin
  • cpe:2.3:a:ritlabs:tinyweb:*:*:*:*:*:*:*:* Versions before 2.01 Vulnerable ·maximmasiutin

Remediation

  • Fix · CNA TinyWeb (maximmasiutin) Fixed in 2.01

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-27613

References

Patch 1

Advisory 2

Other 1

  • TI-2024-04819 Ritlabs TinyWeb Server Request crlf injection CVSS 4.0MEDIUM 6.9
  • TI-2026-18299 TinyWeb CGI Command Injection CVSS 4.0CRITICAL 10.0
  • TI-2026-22760 TinyWeb: Integer Overflow in `_Val` (HTTP Request Smuggling) CVSS 4.0CRITICAL 9.3
  • TI-2026-23191 TinyWeb: HTTP Header Control Character Injection into CGI Environment CVSS 4.0CRITICAL 9.2
  • TI-2024-22622 TinyWeb 1.94 and below allows unauthenticated remote attackers to cause a denial of… CVSS 3.1HIGH 8.6
  • TI-2026-22015 TinyWeb has Unbounded Content-Length Memory Exhaustion (DoS) CVSS 4.0HIGH 8.7
See all 7 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences