Uvnc
Vulnerability activity for Uvnc: what is being exploited, what was published lately, and when the next patch release is due.
Last 30 days
- CVEs
- 0
- Critical (CVSS 9+)
- 0
- Exploited (CISA KEV)
- 0
- With exploit code
- 0
Last 90 days
- CVEs
- 0
- Critical (CVSS 9+)
- 0
- Exploited (CISA KEV)
- 0
- With exploit code
- 0
Last 365 days
- CVEs
- 16
- Critical (CVSS 9+)
- 2
- Exploited (CISA KEV)
- 0
- With exploit code
- 0
Exploited now
None of this vendor's CVEs are on CISA's known-exploited list.
Recent
- 9.8CriticalJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-7840UltraVNC repeater through 1.8.2.2 contains a global buffer overflow in its embedded HTTP administration server. The functions wi_senderr() and wi_replyhdr() in repeater/webgui/webutils.c write the caller-supplied HTTP request URI into a fixed 1000-byte global buffer (hdrbuf) via unchecked sprintf calls. The HTTP receive buffer accepts URIs up to approximately 150 KB (WI_RXBUFSIZE = 153600), so an unauthenticated attacker who can reach the repeater HTTP port (default TCP 80) can overflow hdrbuf b
- 9.1CriticalJul 1, 2026Uvnc ultravnc Auth bypass / access controlCVE-2026-7839UltraVNC repeater through 1.8.2.2 initializes the HTTP administration server with a hardcoded default password. In repeater/webgui/settings.c:197, when settings2.txt is absent on first run the repeater writes the literal string "adminadmi2" as the admin password via strcpy_s(saved_password, 64, "adminadmi2"). The HTTP Basic-auth handler wi_decode_auth() checks this password without rate-limiting or lockout. Any remote attacker who can reach the repeater HTTP port (default TCP 80) can authenticat
- 8.8HighJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-7838UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB protocol failure-response parsing path. In vncviewer/ClientConnection.cpp, the 4-byte network-supplied reasonLen field (type CARD32) is passed as reasonLen+1 to CheckBufferSize(). Because both operands are unsigned 32-bit, a reasonLen of 0xFFFFFFFF overflows to 0, causing CheckBufferSize to allocate only 256 bytes. The subsequent ReadString(m_netbuf, reasonLen) call then performs ReadExact f
- 7.6HighJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-7831UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer _dn[2024] and calls ReadString(_dn, 2024). ReadString writes the NUL terminator at buf[length], i.e., _dn[2024], one byte past the end of the stack buffer. A malicious VNC server can trigger this condition by advertising a desktop name of length 2024
- 7.4HighJul 1, 2026Uvnc ultravnc Crypto / certificateCVE-2026-7830UltraVNC through 1.8.2.2 uses inadequate cryptography in the MS-Logon II authentication scheme (rfbUltraVNC_MsLogonIIAuth). In rfb/dh.cpp the Diffie-Hellman key exchange is performed with parameters that fit in an unsigned 64-bit integer (DH_MAX_BITS controls the prime size). A 64-bit DH key can be broken by Pollard's rho algorithm in under one second on current hardware. Additionally, the private exponent is generated by the rng() function, which multiplies three libc rand() values seeded from
- 7.2HighJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-7829UltraVNC repeater through 1.8.2.2 contains a post-authentication out-of-bounds write in the allow/deny rule parser. In repeater/webgui/settings.c:225-272, after strncpy_s copies a rule token into temp1[rule1] (25-byte destination) or temp2/temp3 (16-byte destination), the code unconditionally writes a NUL terminator at temp1[rule1][len] = 0 without clamping len to the destination size. When an authenticated administrator saves a rule with a token length equal to or greater than the destination s
- 5.3MediumJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-7828UltraVNC repeater through 1.8.2.2 contains an integer overflow in the HTTP request logging path. In repeater/webgui/settings.c:336, the win_log() function allocates list nodes via malloc(sizeof(struct LIST) + strlen(line)), where line is derived from HTTP request URIs. If strlen(line) is sufficiently large, the addition overflows to a value smaller than sizeof(struct LIST), causing a heap allocation smaller than required. The subsequent strcpy of the full string into the undersized allocation pr
- 3.7LowJul 1, 2026Uvnc ultravncCVE-2026-44042UltraVNC repeater through 1.8.2.2 contains an off-by-one error in the Base64 decode helper used for HTTP Basic authentication. In repeater/webgui/webutils.c:817, the wi_uudecode() function checks whether the input length exceeds the output buffer with a strict greater-than comparison (>), while the correct check should be greater-than-or-equal (>=). When strlen(authdata) equals sizeof(decode), the decoded output length (approximately 3/4 of input) does not overflow the buffer in current practice
- 4.3MediumJul 1, 2026Uvnc ultravnc Memory corruptionCVE-2026-44041UltraVNC 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
- 4.8MediumJul 1, 2026Uvnc ultravnc Crypto / certificateCVE-2026-44040UltraVNC through 1.8.2.2 uses a cryptographically weak pseudo-random number generator to produce VNC authentication challenge bytes. In rfb/vncauth.c:119-129, the vncRandomBytes() function seeds libc rand() with time(0) + getpid() + rand() and generates a 16-byte challenge. The combined seed space is approximately 31 bits (libc rand() internal state) and is entirely determined by publicly-observable values (wall-clock time and process ID). An attacker who can observe the authentication exchange
- 7.0HighMar 27, 2026Uvnc ultravncCVE-2026-4962A security flaw has been discovered in UltraVNC up to 1.6.4.0. Affected by this issue is some unknown functionality in the library version.dll of the component Service. The manipulation results in uncontrolled search path. The attack needs to be approached locally. This attack is characterized by high complexity. The exploitation is known to be difficult. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not resp
- 5.5MediumMar 21, 2026Uvnc pchelpwarev2 Memory corruptionCVE-2019-25564PCHelpWareV2 1.0.0.5 contains a denial of service vulnerability that allows local attackers to crash the application by supplying an excessively long string in the Group field. Attackers can paste a buffer overflow payload into the Group property field and click Ok to trigger an application crash.
- 6.2MediumMar 21, 2026Uvnc pchelpwarev2 Denial of serviceCVE-2019-25563PCHelpWareV2 1.0.0.5 contains a denial of service vulnerability that allows local attackers to crash the application by supplying a malformed image file. Attackers can trigger the vulnerability through the Create SC feature by selecting a crafted BMP file with an oversized buffer, causing the application to crash.
- 7.0HighMar 8, 2026Uvnc ultravncCVE-2026-3787A weakness has been identified in UltraVNC 1.6.4.0 on Windows. This affects an unknown function in the library cryptbase.dll of the component Windows Service. This manipulation causes uncontrolled search path. The attack requires local access. A high degree of complexity is needed for the attack. The exploitability is reported as difficult. The vendor was contacted early about this disclosure but did not respond in any way.
- 7.5HighFeb 5, 2026Uvnc ultravnc Memory corruptionCVE-2020-37133UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allows attackers to crash the application. Attackers can paste an overly long string of 300 characters into the Repeater Host property to trigger an application crash.
- 6.2MediumFeb 5, 2026Uvnc ultravnc Memory corruptionCVE-2020-37132UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in its password configuration properties that allows local attackers to crash the application. Attackers can paste an overly long 300-character string into the password field to trigger an application crash and prevent normal launcher functionality.
Top products
- ultravnc14 CVEs in the last year, 2 critical
- pchelpwarev22 CVEs in the last year
Counts cover CVEs and advisories Watch Floor tracks, by the date they became news. Updated every 10 minutes.