CVE-2026-7839EPSS p35.5%
CVE-2026-7839CVE-2026-7839
uvnc / ultravnc
Description
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.
Scoring
| CVSS | 9.1 () |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| EPSS | 0.43% probability of exploitation · percentile 35.5% · 2026-08-15T12:02:44Z |
| Last modified | 2026-07-09 |