CVE-2026-44988
HIGH EPSS 15.2%
Published May 27, 20261mo ago · Modified Jun 17, 20262w ago
8.8 CVSS 3.1
Published May 27, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago
Description
LibVNCClient is a library for easy implementation of a VNC client. In 0.9.15 and earlier, LibVNCClient's Tight encoding decoder uses fixed-size 2048-pixel scratch buffers for the Gradient filter, but it does not reject Tight rectangles whose width is larger than 2048 pixels. A malicious VNC server can send a crafted FramebufferUpdate rectangle using Tight encoding with NoZlib | ExplicitFilter and the Gradient filter. When a LibVNCClient-based client connects, the client processes the server-controlled rectangle width and writes beyond fixed-size Gradient buffers. This vulnerability is fixed with commit 5b270544b85233668b98161323297d418a8f5fd1.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality High
Integrity High
Availability High
Threat Intelligence
EPSS Exploit Probability
15.2% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-787 Out-of-bounds Write Memory Safety
References 2
- github.com https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1
- github.com https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.