Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Uvnc | Ultravnc | <= 1.8.2.2 |
Related Weaknesses (CWE)
References
- https://github.com/ultravnc/UltraVNCProduct
- https://uvnc.com/ProductRelease Notes
- https://www.securin.io/zero-days/cve-2026-44041-vncwc2mb-wcslen-before-bounds-ch
FAQ
What is CVE-2026-44041?
CVE-2026-44041 is a vulnerability with a CVSS score of 4.3 (MEDIUM). 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()...
How severe is CVE-2026-44041?
CVE-2026-44041 has been rated MEDIUM with a CVSS base score of 4.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-44041?
Check the references section above for vendor advisories and patch information. Affected products include: Uvnc Ultravnc.