CVE-2026-44041: falha de média gravidade em uvnc UltraVNC
UltraVNC vncWc2Mb calls wcslen() before validating that the wide string is NUL-terminated
Publicada em · Atualizada em
Aviso por e-mail quando ela entrar no KEV, ganhar PoC pública ou subir de nota.
13Vexday Risk Score
Sem sinal de exploração. Nenhum artefato público de exploração conhecido até agora.
ssvc Trackcvss 4.3epss 0.4%
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:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Produtos afetados
uvnc · UltraVNCCVEs relacionadas — uvnc UltraVNC
No mesmo produto, das mais perigosas para as menos.
CVE-2026-7840CRITICALUltraVNC repeater HTTP server global buffer overflow via long URI (pre-auth RCE)EPSS 2.6%CVE-2026-7838HIGHUltraVNC viewer heap buffer overflow via integer overflow in RFB connection-failure reason lengthEPSS 1.9%CVE-2026-7828MEDIUMUltraVNC repeater integer overflow in win_log malloc leading to heap overflowEPSS 1.4%CVE-2026-7829HIGHUltraVNC repeater authenticated out-of-bounds write in rule parser via oversized tokenEPSS 0.9%CVE-2026-7831HIGHUltraVNC viewer off-by-one stack overflow in ServerInit desktop name parsingEPSS 0.7%CVE-2026-7839CRITICALUltraVNC repeater ships hardcoded default admin password allowing unauthenticated admin accessEPSS 0.7%