Vulnerability Report

CVE-2026-44041

Title: Out-of-bounds Read in UltraVNC Wide-String Conversion

Memory Corruption

Proof Of Concept

No public PoC currently indexed for CVE-2026-44041.

CWE Category CWE-125

Published Date Jul 01, 2026

Modified Date Jul 09, 2026

Exploit Status Not Found

Score 4.3 CVSS v3.1

Exploit Probability (EPSS)

0.41%

Vulnerability Summary

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.

Impacted Vendors

uvnc 1

Reference Links

https://github.com/ultravnc/UltraVNC https://uvnc.com/

CVSS v3.1

Source Entity 33c584b5-0579-4c06-b2a0-8d8329fcab9c

Severity MEDIUM

4.3

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L