Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M
CVE-2026-27633TinyWeb has Unbounded Content-Length Memory Exhaustion (DoS)
High 8.7
In plain English
A high-severity uncontrolled resource consumption in TinyWeb from maximmasiutin. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).
Official 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).
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| maximmasiutin | TinyWeb | < 2.02 |
Weakness: CWE-400 · 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
References
- https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-992w-gmcm-fmgr x_refsource_CONFIRM
- https://github.com/maximmasiutin/TinyWeb/commit/1cb5a1d x_refsource_MISC
- https://www.masiutin.net/tinyweb-cve-2026-27633.html x_refsource_MISC