Vulnerability Details CVE-2026-44041
UltraVNC through 1.8.2.2 contains an out-of-bounds read in the wide-string to multibyte conversion helper. In rfb/dh.cpp:204, the vncWc2Mb() function passes a caller-supplied WCHAR pointer to wcslen() before any bounds check. If the caller provides a wide-character buffer that is not properly NUL-terminated, wcslen() reads past the end of the buffer until it encounters a NUL wchar, resulting in an out-of-bounds read. Under typical Win32 API usage this requires an abnormal caller contract. Impact is limited to a potential information disclosure from adjacent memory regions or a process crash (denial of service) if the over-read crosses a page boundary.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 16.8%
CVSS Severity
CVSS v3 Score 4.3
Products affected by CVE-2026-44041
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cpe:2.3:a:uvnc:ultravnc:1.0.9.6.2
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cpe:2.3:a:uvnc:ultravnc:1.1.8.9
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cpe:2.3:a:uvnc:ultravnc:1.1.9.3
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cpe:2.3:a:uvnc:ultravnc:1.1.9.6
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cpe:2.3:a:uvnc:ultravnc:1.2.0.5
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cpe:2.3:a:uvnc:ultravnc:1.2.0.9
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cpe:2.3:a:uvnc:ultravnc:1.2.1.0
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cpe:2.3:a:uvnc:ultravnc:1.2.1.2
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cpe:2.3:a:uvnc:ultravnc:1.2.1.6
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cpe:2.3:a:uvnc:ultravnc:1.2.1.7
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cpe:2.3:a:uvnc:ultravnc:1.2.2.2
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cpe:2.3:a:uvnc:ultravnc:1.2.2.3
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cpe:2.3:a:uvnc:ultravnc:1.2.2.4
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cpe:2.3:a:uvnc:ultravnc:1.2.4.0
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cpe:2.3:a:uvnc:ultravnc:1.3.2
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cpe:2.3:a:uvnc:ultravnc:1.3.4
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cpe:2.3:a:uvnc:ultravnc:1.3.4.1
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cpe:2.3:a:uvnc:ultravnc:1.3.4.2
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cpe:2.3:a:uvnc:ultravnc:1.3.6.0
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cpe:2.3:a:uvnc:ultravnc:1.3.8.0
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cpe:2.3:a:uvnc:ultravnc:1.3.8.1
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cpe:2.3:a:uvnc:ultravnc:1.4.0.5
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cpe:2.3:a:uvnc:ultravnc:1.4.0.6
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cpe:2.3:a:uvnc:ultravnc:1.4.0.9
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cpe:2.3:a:uvnc:ultravnc:1.4.2.0
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cpe:2.3:a:uvnc:ultravnc:1.4.3.0
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cpe:2.3:a:uvnc:ultravnc:1.4.3.1
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cpe:2.3:a:uvnc:ultravnc:1.4.3.5
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cpe:2.3:a:uvnc:ultravnc:1.4.3.6
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cpe:2.3:a:uvnc:ultravnc:1.5.0.0
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cpe:2.3:a:uvnc:ultravnc:1.6.0.0
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cpe:2.3:a:uvnc:ultravnc:1.6.1.0
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cpe:2.3:a:uvnc:ultravnc:1.6.4.0
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cpe:2.3:a:uvnc:ultravnc:1.8.2.2