Out-of-bounds Write Affecting libvncserver-debuginfo package, versions <0:0.9.9-14.amzn2.0.3


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.44% (36th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-AMZN2-LIBVNCSERVERDEBUGINFO-17286487
  • published10 Jun 2026
  • disclosed27 May 2026

Introduced: 27 May 2026

CVE-2026-44988  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 libvncserver-debuginfo to version 0:0.9.9-14.amzn2.0.3 or higher.
This issue was patched in ALAS2-2026-3331.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libvncserver-debuginfo package and not the libvncserver-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

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 Base Scores

version 3.1