CVE-2026-27630: TinyWeb vulnerable to Remote Denial of Service via Thread/Connection Exhaustion (Slowloris)

Published Feb 25, 2026
·
Updated

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.

Affected Software

2 affected components
TinyWeb TinyWeb<2.02
Ritlabs TinyWeb<2.02

Event History

Feb 25, 2026
CVE Published
via MITRE·11:05 PM
Data Sourced
via MITRE·11:05 PM
DescriptionWeakness
Feb 26, 2026
Data Sourced
via NVD·12:16 AM
RemedyDescriptionSeverityWeaknessAffected Software
Oct 1, 58139
Event
via FIRST·11:05 AM
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Frequently Asked Questions

1

What is the severity of CVE-2026-27630?

CVE-2026-27630 is classified as a high severity vulnerability due to its potential for causing a Remote Denial of Service via Thread/Connection Exhaustion.

2

How do I fix CVE-2026-27630?

To mitigate CVE-2026-27630, upgrade to TinyWeb version 2.02 or later, which resolves the vulnerability.

3

What type of attack is CVE-2026-27630 associated with?

CVE-2026-27630 is associated with a Denial of Service (DoS) attack known as Slowloris.

4

Which versions of TinyWeb are affected by CVE-2026-27630?

TinyWeb versions prior to 2.02 are affected by CVE-2026-27630.

5

What is the impact of CVE-2026-27630 on users?

The impact of CVE-2026-27630 on users can lead to server unavailability as the vulnerability allows attackers to exhaust server resources.

Contact

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