CVE-2026-44988
highpriority · track · 0EPSS 0.004 · 37 %ileEURUEPSS · scored 2026-10-23
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
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base score 0–10 · higher = more severe · hover a vector to decode
ssvc
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weaknesses
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affected products (13)
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also known as (3)
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sources
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references (6)
External citations — patches, advisories, analysis.
- https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1cnnvd
- https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58cnnvd
- https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1enisa_euvd
- https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58enisa_euvd
- https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1nvd
- https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58nvd
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