RealVNC up to P4.4.2 Encoding Type CMsgReader::readRect input validation

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.
6.4$0-$5k0.00

Summaryinfo

A vulnerability was found in RealVNC up to P4.4.2. It has been declared as problematic. The affected element is the function CMsgReader::readRect of the component Encoding Type Handler. Executing a manipulation can lead to input validation. This vulnerability is handled as CVE-2008-4770. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability has been found in RealVNC up to P4.4.2 and classified as critical. This vulnerability affects the function CMsgReader::readRect of the component Encoding Type Handler. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The CMsgReader::readRect function in the VNC Viewer component in RealVNC VNC Free Edition 4.0 through 4.1.2, Enterprise Edition E4.0 through E4.4.2, and Personal Edition P4.0 through P4.4.2 allows remote VNC servers to execute arbitrary code via crafted RFB protocol data, related to "encoding type."

The bug was discovered 01/12/2009. The weakness was released 10/20/2008 with RealVNC (Website). The advisory is shared for download at realvnc.com. This vulnerability was named CVE-2008-4770 since 10/28/2008. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available.

It is declared as proof-of-concept. As 0-day the estimated underground price was around $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 67799 (Oracle Linux 3 / 4 / 5 : vnc (ELSA-2009-0261)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Oracle Linux Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 117191 (CentOS Security Update for VNC (CESA-2009:0261)).

Upgrading eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at realvnc.com. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published 4 months after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (47937), Tenable (67799), SecurityFocus (BID 33263†), OSVDB (50050†) and Secunia (SA34184†). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 6.4

VulDB Base Score: 7.3
VulDB Temp Score: 6.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Proof-of-Concept

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 67799
Nessus Name: Oracle Linux 3 / 4 / 5 : vnc (ELSA-2009-0261)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

OpenVAS ID: 63303
OpenVAS Name: Debian Security Advisory DSA 1716-1 (vnc4)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Patch: realvnc.com
Fortigate IPS: 🔍

Timelineinfo

10/20/2008 🔍
10/20/2008 +0 days 🔍
10/20/2008 +0 days 🔍
10/28/2008 +7 days 🔍
10/28/2008 +0 days 🔍
10/29/2008 +1 days 🔍
11/25/2008 +27 days 🔍
01/12/2009 +48 days 🔍
01/16/2009 +4 days 🔍
01/31/2009 +15 days 🔍
07/12/2013 +1623 days 🔍
05/25/2025 +4335 days 🔍

Sourcesinfo

Advisory: realvnc.com
Organization: RealVNC
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2008-4770 (🔍)
GCVE (CVE): GCVE-0-2008-4770
GCVE (VulDB): GCVE-100-3856

OVAL: 🔍

X-Force: 47937 - RealVNC RFB protocol code execution, High Risk
SecurityFocus: 33263 - RealVNC 4.1.2 'vncviewer.exe' RFB Protocol Remote Code Execution Vulnerability
Secunia: 34184 - Gentoo update for vnc, Moderately Critical
OSVDB: 50050 - RealVNC VNC Viewer common/rfb/CMsgReader.cxx CMsgReader::readRect() Function Message Handling Arbitrary Code Execution
Vulnerability Center: 19877 - RealVNC < 4.1.3 CMsgReader Remote Code Execution or DoS Vulnerability, High
Vupen: ADV-2008-2868

Entryinfo

Created: 10/29/2008 10:55
Updated: 05/25/2025 06:45
Changes: 10/29/2008 10:55 (95), 08/20/2019 09:16 (1), 05/25/2025 06:45 (18)
Complete: 🔍
Cache ID: 216:84C:103

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

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Want to know what is going to be exploited?

We predict KEV entries!