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Openvpn CVE-2025-13751

| EUVDEUVD-2025-200999 MEDIUM
Allocation of Resources Without Limits or Throttling (CWE-770)
2025-12-03 security@openvpn.net
5.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V2 - Validation and Business Logic Resource allocation 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.

Impact

Service disruption affecting availability. In critical infrastructure, DoS can have cascading effects on dependent systems. With a CVSS score of 5.5 (MEDIUM), this represents a moderate risk.

Exploit ScenarioDerived

An attacker sends specially crafted requests that cause excessive resource consumption (CPU, memory, disk) or trigger a crash in the target application.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 15, 2026

Interactive service agent in OpenVPN version 2.5.0 through 2.6.16 and 2.7_alpha1 through 2.7_rc2 on Windows allows a local authenticated user to connect to the service and trigger an error causing a local denial of service.

Earlier versions of this analysis (1)
v1 Mar 15, 2026 - 16:14 CVSS 5.5

RemediationAI

Implement rate limiting and input validation. Use timeout mechanisms for resource-intensive operations. Deploy DDoS protection where applicable.

Affected VersionsENISA

OpenVPN 2.5.0 ≤2.6.16
OpenVPN 2.7_alpha1 ≤2.7_rc2
OpenVPN 2.5.0 ≤2.7_rc2

Affected Packages

euvd openvpn no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

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

Technical ContextAI · show details

A denial of service vulnerability allows an attacker to disrupt the normal functioning of a system, making it unavailable to legitimate users. This vulnerability is classified as Allocation of Resources Without Limits or Throttling (CWE-770).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat 5.5 LOW

Primary rating from NVD.

CVSS VectorNVD

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

Lifecycle Timeline

2
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
CVE Published
Dec 03, 2025 - 17:15 nvd
MEDIUM 5.5

Executive ViewAI

Why It Matters

Organizations using OpenVPN should be aware of moderate risk from CVE-2025-13751 rated CVSS 5.5. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score
0.0%
Top 97% exploitable
Data Quality
5 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 MEDIUM
CISA KEV No
Public POC No
EPSS 0.0%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
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
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Low

Priority Score

28
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +28
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.

CVE-2018-7544 CRITICAL POC
9.1 Mar 16

A cross-protocol scripting issue was discovered in the management interface in OpenVPN through 2.4.5. Rated critical sev

CVE-2017-7478 HIGH POC
7.5 May 15

OpenVPN version 2.3.12 and newer is vulnerable to unauthenticated Denial of Service of server via received large control

CVE-2020-9442 HIGH POC
7.8 Feb 28

OpenVPN Connect 3.1.0.361 on Windows has Insecure Permissions for %PROGRAMDATA%\OpenVPN Connect\drivers\tap\amd64\win10,

CVE-2018-9336 HIGH POC
7.8 May 01

openvpnserv.exe (aka the interactive service helper) in OpenVPN 2.4.x before 2.4.6 allows a local attacker to cause a do

CVE-2017-5868 MEDIUM POC
6.1 May 26

CRLF injection vulnerability in the web interface in OpenVPN Access Server 2.1.4 allows remote attackers to inject arbit

CVE-2014-9104 MEDIUM POC
6.8 Nov 26

Multiple cross-site request forgery (CSRF) vulnerabilities in the XML-RPC API in the Desktop Client in OpenVPN Access Se

CVE-2023-46850 CRITICAL
9.8 Nov 11

Use after free in OpenVPN version 2.6.0 to 2.6.6 may lead to undefined behavoir, leaking memory buffers or remote execut

CVE-2019-25429 MEDIUM POC
6.1 Feb 19

Comodo Dome Firewall 2.7.0 contains a reflected cross-site scripting vulnerability that allows attackers to inject malic

CVE-2019-25428 MEDIUM POC
6.1 Feb 19

Comodo Dome Firewall 2.7.0 contains multiple reflected cross-site scripting vulnerabilities in the openvpn_users endpoin

CVE-2017-12166 CRITICAL
9.8 Oct 04

OpenVPN versions before 2.3.3 and 2.4.x before 2.4.4 are vulnerable to a buffer overflow vulnerability when key-method 1

CVE-2024-1305 CRITICAL
9.8 Jul 08

tap-windows6 driver version 9.26 and earlier does not properly check the size data of incomming write operations which a

CVE-2024-27903 CRITICAL
9.8 Jul 08

OpenVPN plug-ins on Windows with OpenVPN 2.6.9 and earlier could be loaded from any directory, which allows an attacker

Vendor StatusVendor

Debian

openvpn
Release Status Fixed Version Urgency
bullseye fixed 2.5.1-3 -
bullseye (security) fixed 2.5.1-3+deb11u2 -
bookworm, bookworm (security) fixed 2.6.3-1+deb12u4 -
trixie (security), trixie fixed 2.6.14-1+deb13u1 -
forky, sid fixed 2.7.0-1 -
(unstable) not-affected - -

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