PatchTheCVECVE-2026-44041: UltraVNC through 1.8.2.2 contains an out-of-bounds read in the wide-string to multibyte conversion helper
CVE-2026-44041 is a medium-severity flaw (CVSS 4.3) affecting ultravnc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 4.3 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 0.4% (top 65%) |
| CISA exploited list | No |
| Weakness | CWE-125 |
| Published | 2026-07-01 |
| Last modified | 2026-10-25 |
Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-44041?
ultravnc: upgrade to newer than 1.8.2.2. Exact commands for each OS are on this page.
Is CVE-2026-44041 being exploited?
CVE-2026-44041 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-44041 affect?
CVE-2026-44041 affects ultravnc. Severity is medium (CVSS 4.3). 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
How urgent is CVE-2026-44041?
Priority 24/100. No elevated risk signals yet.
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