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Tinyweb CVE-2026-27630

HIGH
Uncontrolled Resource Consumption (CWE-400)
2026-02-26 security-advisories@github.com
7.5
CVSS 3.1 · GitHub Advisory
View

Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Open numerous connections to TinyWeb server
  2. Exploit
    Send HTTP request data extremely slowly (1 byte per minutes)
  3. Execution
    Exhaust server thread pool and memory
  4. Impact
    Server becomes unresponsive to legitimate requests

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource consumption limits
MITRE ATT&CK

1 technique across 1 tactic: Impact

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

TinyWeb versions prior to 2.02 without connection limits or request timeouts. No authentication required. Attacker needs network access to the server listening on HTTP/HTTPS ports (default or configured).

Impact

CVSS 7.5 (HIGH). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required. Exploitable via remote/network.

Exploit ScenarioDerived

A remote attacker without authentication could exploit this vulnerability to compromise the affected system.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

TinyWeb versions prior to 2.02 lack connection limits and request timeouts, enabling unauthenticated remote attackers to trigger denial of service through Slowloris attacks by maintaining numerous concurrent connections and transmitting data at minimal rates. The vulnerability affects all systems running vulnerable TinyWeb instances, with attackers capable of exhausting server resources and rendering services unavailable. A patch is available that implements connection limits and idle timeouts to mitigate the attack vector.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 21:55 CVSS 7.5

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. [CVSS 7.5 HIGH]

RemediationAI

A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Classified as CWE-400 (Uncontrolled Resource Consumption). Affects Tinyweb. 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).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

GitHub Advisory PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

2
Patch released
Feb 28, 2026 - 01:01 nvd
Patch available
CVE Published
Feb 26, 2026 - 00:16 nvd
HIGH 7.5

DescriptionGitHub Advisory

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.

Executive ViewAI

Why It Matters

TinyWeb servers running versions prior to 2.02 are vulnerable to Slowloris denial of service attacks that can render web services unavailable to legitimate users. Organizations using affected TinyWeb instances risk service disruption and potential business continuity impact until patched.

Business Impact: Medium
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.1%
Top 68% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Medium

Priority Score

38
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:ritlabs:tinyweb:*:*:*:*:*:*:*:*
CVE-2026-67185 HIGH POC
8.7 Jul 28

Path traversal in TinyWeb through 0.0.8 allows unauthenticated remote attackers to read arbitrary files from the server'

CVE-2026-67184 HIGH POC
8.7 Jul 28

Null pointer dereference in TinyWeb 0.0.8 and earlier allows unauthenticated remote attackers to crash worker processes

CVE-2026-67183 HIGH POC
8.7 Jul 28

Memory exhaustion vulnerability in TinyWeb HTTP server (through 0.0.8) enables unauthenticated remote attackers to cause

CVE-2024-34199 HIGH POC
8.6 May 14

TinyWeb 1.94 and below allows unauthenticated remote attackers to cause a denial of service (Buffer Overflow) when sendi

CVE-2026-22781 CRITICAL
9.8 Jan 12

TinyWeb HTTP Server before 1.98 has OS command injection via CGI ISINDEX query parameters. The query string is passed as

CVE-2026-27613 CRITICAL
9.8 Feb 25

Unauthenticated command injection in TinyWeb HTTP/HTTPS server for Win32 before 2.01 allows remote attackers to execute

CVE-2024-5193 MEDIUM POC
5.5 May 22

A security vulnerability has been detected in Ritlabs TinyWeb Server 1.94. Rated medium severity (CVSS 5.5), this vulner

CVE-2026-28497 CRITICAL
9.1 Mar 06

Integer overflow in TinyWeb before 2.03.

CVE-2026-29046 HIGH
8.2 Mar 06

TinyWeb versions prior to 2.04 fail to properly sanitize control characters and encoded sequences (CR, LF, NUL) in HTTP

CVE-2026-27633 HIGH
7.5 Feb 26

TinyWeb versions prior to 2.02 are vulnerable to denial of service through memory exhaustion when unauthenticated attack

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