CVE-2026-27633CWE-400

TinyWeb has Unbounded Content-Length Memory Exhaustion (DoS)

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 have a Denial of Service (DoS) vulnerability via memory exhaustion. Unauthenticated remote attackers can send an HTTP POST request to the server with an exceptionally large `Content-Length` header (e.g., `2147483647`). The server continuously allocates memory for the request body (`EntityBody`) while streaming the payload without enforcing any maximum limit, leading to all available memory being consumed and causing the server to crash. Anyone hosting services using TinyWeb is impacted. Version 2.02 fixes the issue. The patch introduces a `CMaxEntityBodySize` limit (set to 10MB) for the maximum size of accepted payloads. As a temporary workaround if upgrading is not immediately possible, consider placing the server behind a Web Application Firewall (WAF) or reverse proxy (like nginx or Cloudflare) configured to explicitly limit the maximum allowed HTTP request body size (e.g., `client_max_body_size` in nginx).

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
2026-02-25T23:07Z
EPSS history
Timeline
  • 25 FEB 23:07Z
    TinyWeb has Unbounded Content-Length Memory Exhaustion (DoS)
    cvelistv5