Out-of-bounds Write 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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-UNMANAGED-ULTRAVNCULTRAVNC-17746975
- published1 Jul 2026
- disclosed1 Jul 2026
- creditUnknown
Introduced: 1 Jul 2026
CVE-2026-7840 (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 Out-of-bounds Write via the wi_senderr and wi_replyhdr functions. An attacker can execute arbitrary code on the host by sending a specially crafted HTTP request with an excessively long URI to the embedded HTTP administration server before authentication.