🛡️ OESA-2026-2565 — libvncserver

🟠 CVSS 8.0 — High ✅ No Known Exploit OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

libvncserver security update

libvncserver is a set of programs using the RFB (Remote Frame Buffer) protocol. They are designed to "export" a frame buffer via net: you set up a server and can connect to it via VNC viewers. If the server supports WebSockets (which LibVNCServer does), you can also connect using an in-browser VNC viewer like noVNC. It is already in wide use for administration, but it is not that easy to program a server yourself.

Security Fix(es):

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 software

OESA-2026-2565 is recorded against 1 package.

  • libvncserver (fixed in 0.9.13-5.oe2203sp4)

Timeline and source

Published on 5 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

www.openeuler.org (Advisory)
nvd.nist.gov (Advisory)

Details

Severity HIGH
CVSS Score 8.0
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-05
Updated 2026-08-12
Modified 2026-06-05
Fix URL N/A

Affected Packages

Software From version Fixed in
libvncserver — 0.9.13-5.oe2203sp4

Similar Threats

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