CVE-2026-7839
UltraVNC repeater ships hardcoded default admin password allowing unauthenticated admin access
- State
- Published
- Severity
- 9.1 Critical
- Published
- Jul 1, 2026
- Updated
- Jul 9, 2026
- Reserved
- May 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | securin |
Weaknesses
- CWE-798 Use of Hard-coded Credentials
Affected Products
| Product | Versions |
|---|---|
UltraVNCuvnc |
|
References
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