VDB-344528 · CVE-2020-37134 · Exploit 48291

UltraVNC Viewer 1.2.4.0 allocation of resources

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.7	$0-$5k	0.00

Summaryinfo

A vulnerability, which was classified as problematic, was found in UltraVNC Viewer 1.2.4.0. This affects an unknown function. Such manipulation leads to allocation of resources. This vulnerability is listed as CVE-2020-37134. The attack may be performed from remote. In addition, an exploit is available.

Detailsinfo

A vulnerability was found in UltraVNC Viewer 1.2.4.0. It has been rated as problematic. Affected by this issue is some unknown functionality. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. CVE summarizes:

UltraVNC Viewer 1.2.4.0 contains a denial of service vulnerability that allows attackers to crash the application by manipulating VNC Server input. Attackers can generate a malformed 256-byte payload and paste it into the VNC Server connection dialog to trigger an application crash.

The weakness was presented by chuyreds as 48291. The advisory is shared for download at exploit-db.com. This vulnerability is handled as CVE-2020-37134 since 02/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are unknown but a public exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

The exploit is available at exploit-db.com. It is declared as proof-of-concept.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2020-31034). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Connectivity Software

Vendor

UltraVNC

Name

Viewer

Version

1.2.4.0

License

open-source

CPE 2.3info

🔒

CPE 2.2info

🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.9
VulDB Meta Temp Score: 5.7

VulDB Base Score: 4.3
VulDB Temp Score: 3.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Access: Public
Status: Proof-of-Concept
Download: 🔒

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

02/03/2026 CVE reserved
02/05/2026 +2 days Advisory disclosed
02/05/2026 +0 days VulDB entry created
02/06/2026 +1 days VulDB entry last update

Sourcesinfo

Advisory: 48291
Researcher: chuyreds
Status: Not defined

CVE: CVE-2020-37134 (🔒)
GCVE (CVE): GCVE-0-2020-37134
GCVE (VulDB): GCVE-100-344528
EUVD: 🔒
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 02/05/2026 18:00
Updated: 02/06/2026 16:27
Changes: 02/05/2026 18:00 (78), 02/06/2026 16:27 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.