CVE-2026-7839
UltraVNC repeater ships hardcoded default admin password allowing unauthenticated admin access
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.
INFO
Published Date :
July 1, 2026, 3:33 a.m.
Last Modified :
July 1, 2026, 3:33 a.m.
Remotely Exploit :
Yes !
Source :
securin
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | 33c584b5-0579-4c06-b2a0-8d8329fcab9c |
Solution
- Change the default password from 'adminadmi2' immediately.
- Secure the administration interface with strong credentials.
- Ensure no default passwords remain after configuration.
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