CVE-2026-27633

7.5 HIGH
Published: February 26, 2026 Modified: February 28, 2026
View on NVD

Description

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).

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/maximmasiutin/TinyWeb/commit/1cb5a1d
Source: security-advisories@github.com
Patch
https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-992w-gmcm-fmgr
Source: security-advisories@github.com
Vendor Advisory
https://www.masiutin.net/tinyweb-cve-2026-27633.html
Source: security-advisories@github.com
Third Party Advisory

3 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.1%
32th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

ritlabs