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-17747018
- published1 Jul 2026
- disclosed1 Jul 2026
- creditUnknown
Introduced: 1 Jul 2026
CVE-2026-44042 (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 through the wi_uudecode function in the Base64 decode process. An attacker can cause a one-byte write at the boundary of a 1024-byte stack buffer by supplying input data that matches the buffer size, potentially leading to memory corruption under constrained conditions. This is only exploitable if the HTTP request bounds or buffering constraints are altered to allow the off-by-one write to affect memory outside the intended buffer.