Off-by-one Error Affecting ultravnc/UltraVNC package, versions [0,]
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-ULTRAVNCULTRAVNC-17746982
- published1 Jul 2026
- disclosed1 Jul 2026
- creditUnknown
Introduced: 1 Jul 2026
CVE-2026-7831 (opens in a new tab)How to fix?
There is no fixed version for ultravnc/UltraVNC.
Overview
Affected versions of this package are vulnerable to Off-by-one Error in the ServerInit message handler when processing a server-supplied desktop name length of exactly 2024. An attacker can overwrite adjacent stack data or corrupt the stack canary by supplying a specially crafted desktop name length, potentially leading to process termination or unintended behavior when a user connects to a malicious server. This is only exploitable if the user connects to a malicious VNC server.