CVE-2026-7839 (GCVE-0-2026-7839)

Vulnerability from cvelistv5 – Published: 2026-07-01 03:33 – Updated: 2026-07-09 04:35
VLAI
Title
UltraVNC repeater ships hardcoded default admin password allowing unauthenticated admin access
Summary
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.
Severity
9.1 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-01 12:32 UTC
CWE
  • CWE-798 - Use of Hard-coded Credentials
Assigner
securin CNA under the mitre root
CNA scorecard B 80/100 over 71 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
uvnc UltraVNC Affected: 0 , ≤ 1.8.2.2 (custom)
guessed Create a notification for this product.
Credits
Arjun Basnet, Securin (arjun.basnet@securin.io)
Show details on NVD website
To clipboard 

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