Resource exhaustion in Maximmasiutin Tinyweb
CVE-2026-27633
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).
Vulnerability class: DoS (Denial of Service)
EPSS: 0.004 (36.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Maximmasiutin Tinyweb — versions < 2.02
- Ritlabs Tinyweb
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-27633?
- CVE-2026-27633 is a high-severity vulnerability in Maximmasiutin Tinyweb, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2026-02-26.
- How severe is CVE-2026-27633?
- High severity. CVSS v3 base score is 7.5 out of 10.