Amazon Linux 2 Security Advisory: ALAS2-2026-3331
Advisory Released Date: 2026-06-08
Advisory Updated Date: 2026-06-08
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. (CVE-2026-44988)
Affected Packages:
libvncserver
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update libvncserver or yum update --advisory ALAS2-2026-3331 to update your system.
aarch64:
libvncserver-0.9.9-14.amzn2.0.3.aarch64
libvncserver-devel-0.9.9-14.amzn2.0.3.aarch64
libvncserver-debuginfo-0.9.9-14.amzn2.0.3.aarch64
i686:
libvncserver-0.9.9-14.amzn2.0.3.i686
libvncserver-devel-0.9.9-14.amzn2.0.3.i686
libvncserver-debuginfo-0.9.9-14.amzn2.0.3.i686
src:
libvncserver-0.9.9-14.amzn2.0.3.src
x86_64:
libvncserver-0.9.9-14.amzn2.0.3.x86_64
libvncserver-devel-0.9.9-14.amzn2.0.3.x86_64
libvncserver-debuginfo-0.9.9-14.amzn2.0.3.x86_64