CVE-2026-44041UltraVNC through 1.8.2.2 contains an out-of-bounds read in the wide-string to multibyte conversion helper.
Updated under an hour ago ()
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It affects uvnc ultravnc. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 6.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
- Weakness (CWE)
- CWE-125
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Jul 9, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
uvnc ultravnc uvnc:ultravnc | through 1.8.2.2 | NVD |
References
- https://github.com/ultravnc/UltraVNCproduct
- https://uvnc.com/product, release-notes
- https://www.securin.io/zero-days/cve-2026-44041-vncwc2mb-wcslen-before-bounds-check-ultravnc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.