CVE-2026-27630CWE-400

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

High · published February 25, 2026

CVSS v4.0
8.7
EPSS
1%
Percentile
57.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.7 · HIGH
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
EPSS
0.00842 · 57.5th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-02-25T23:05Z
EPSS history
Timeline
  • 25 FEB 23:05Z
    TinyWeb vulnerable to Remote Denial of Service via Thread/Connection Exhaustion (Slowloris)
    cvelistv5