CVE-2026-27630 PUBLISHED

TinyWeb vulnerable to Remote Denial of Service via Thread/Connection Exhaustion (Slowloris)

Assigner: GitHub_M
Reserved: 20.02.2026 Published: 25.02.2026 Updated: 25.02.2026

TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. Versions prior to version 2.02 are vulnerable to a Denial of Service (DoS) attack known as Slowloris. The server spawns a new OS thread for every incoming connection without enforcing a maximum concurrency limit or an appropriate request timeout. An unauthenticated remote attacker can exhaust server concurrency limits and memory by opening numerous connections and sending data exceptionally slowly (e.g. 1 byte every few minutes). Anyone hosting services using TinyWeb is impacted. Version 2.02 fixes the issue. The patch introduces a CMaxConnections limit (set to 512) and a CConnectionTimeoutSecs idle timeout (set to 30 seconds). As a temporary workaround if upgrading is not immediately possible, consider placing the server behind a robust reverse proxy or Web Application Firewall (WAF) such as nginx, HAProxy, or Cloudflare, configured to buffer incomplete requests and aggressively enforce connection limits and timeouts.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 8.7

Product Status

Vendor maximmasiutin
Product TinyWeb
Versions
  • Version < 2.02 is affected

References

Problem Types

  • CWE-400: Uncontrolled Resource Consumption CWE