Tight JPEG decoding in TightVNC and UltraVNC viewers contains a heap-based buffer overflow because an attacker-controlled framebuffer rectangle width is not validated against a fixed-size decoding buffer. A malicious VNC server can cause an out-of-bounds heap write when a user connects, resulting in application crash and potentially other memory-corruption impacts.
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Fixes

Solution

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Workaround

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History

Fri, 13 Nov 2026 00:45:00 +0000

Type Values Removed Values Added
Description Tight JPEG decoding in TightVNC and UltraVNC viewers contains a heap-based buffer overflow because an attacker-controlled framebuffer rectangle width is not validated against a fixed-size decoding buffer. A malicious VNC server can cause an out-of-bounds heap write when a user connects, resulting in application crash and potentially other memory-corruption impacts.
Title Tight JPEG decoding in TightVNC and UltraVNC viewers contains a heap-based buffer overflow vulnerability
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: certcc

Published:

Updated: 2026-11-13T00:08:32.021Z

Reserved: 2026-11-13T00:02:00.631Z

Link: CVE-2026-128321

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses

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