Vulnerability Report

CVE-2026-27630

Title: DoS (Slowloris) in TinyWeb

DoS

Proof Of Concept

No public PoC currently indexed for CVE-2026-27630.

CWE Category CWE-400
Published Date Feb 26, 2026
Modified Date Feb 28, 2026
Exploit Status Not Found
Score 8.7 CVSS v4.0
Exploit Probability (EPSS)
0.44%

Vulnerability Summary

CVE-2026-27630: 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.

Impacted Vendors

R
ritlabs 1
R
rit_research_labs 1

Reference Links

https://github.com/maximmasiutin/TinyWeb/commit/23268c8 https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-ccv5-8948-c99c https://www.masiutin.net/tinyweb-cve-2026-27630.html
CVSS v4.0
Source Entity [email protected]
Severity HIGH
8.7
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.5
Attack Vector
NETWORK
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-27630 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected Stack

No specific products linked.