CVE-2026-44988

8.8 HIGH 0.2% exploit odds Fix listed Memory safety Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in, but needs a user to act. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-05-27 15:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-26 11:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 8.8 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-05-27 15:16 UTC
Last modified: 2026-10-26 11:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-787 · Out-of-bounds write
Record status: Awaiting Analysis

Attack profile CVSS 3.1 · 8.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-44988.md and follow it. Check whether this project is affected by CVE-2026-44988. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record