PT-2026-54478 · Uvnc · Ultravnc

Published 2026-07-01 · Updated 2026-07-01 · CVE-2026-44041

Mitre

CVSS v3.1

4.3

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Fix

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

CVE-2026-44041

Affected Products

Ultravnc

References · 3

• https://nvd.nist.gov/vuln/detail/CVE-2026-44041 · Security Note
• https://uvnc.com · Vendor Advisory
• https://github.com/ultravnc/UltraVNC · Note