CVE-2026-7839: uvnc UltraVNC vulnerability
uvnc · UltraVNC
Vendor fix available · Affected: uvnc UltraVNC · Exploitation: not established
ExploitationNot established
Not in CISA KEV as of catalogue 2026.11.13 (13 Nov)
- In CISA KEV: not seen
- Exploited (reported): not seen
- Scanning observed: not seen
- Proof of concept public: not seen
- Not establishedNothing in the sources we check
Higher than 51% of scored CVEs
DescriptionNVD
UltraVNC 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 authenticate as administrator using the well-known default credential on a fresh or unmodified installation, gaining full control of the repeater configuration including allow/deny rules and session visibility.
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 3 Jul.
- UltraVNC Repeater CVE-2026-7840 lets attackers run code remotelySecurityOnline · first in our coverage · mentions it in passing
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