Summaryinfo

A vulnerability was found in LibVNC Server up to 0.9.15. It has been classified as critical. Impacted is the function HandleUltraZipBPP of the component VNC Handler. This manipulation causes out-of-bounds. The identification of this vulnerability is CVE-2026-32853. It is possible to initiate the attack remotely. There is no exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability classified as critical was found in LibVNC Server up to 0.9.15. Affected by this vulnerability is the function HandleUltraZipBPP of the component VNC Handler. The manipulation with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.

The weakness was shared by Kazuma Matsumoto. It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-32853 since 03/16/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Applying the patch 009008e2f4d5a54dd71f422070df3af7b3dbc931 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• LibVNC

Name

• Server

Version

• 0.9.0
• 0.9.1
• 0.9.2
• 0.9.3
• 0.9.4
• 0.9.5
• 0.9.6
• 0.9.7
• 0.9.8
• 0.9.9
• 0.9.10
• 0.9.11
• 0.9.12
• 0.9.13
• 0.9.14
• 0.9.15

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CPE 2.2info

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