Log in / Sign up

Vulnerability details

CVE-2026-7839

uvnc UltraVNC

UltraVNC repeater ships hardcoded default admin password allowing unauthenticated admin access

CVSS 3.1
9.1Critical

Official 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.

CVSS scores

ScoreVersionSourceVector
9.1Critical 3.1 CVEProject cvelistV5 (CNA) (securin) CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

VendorProductVersionsSource
uvnc UltraVNC v ≤ 1.8.2.2 CVEProject cvelistV5 (CNA)

References and advisories

3
Kolun on Telegram @kolunsec Exploited CVEs, key news and a daily digest Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.

Details

Published
2026-07-01
Last updated
2026-07-09
State
Published
Assigner (CNA)
securin

Exploit prediction (EPSS)

0.65%
Probability of exploitation in 30 days
51.6%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Total

Weaknesses (CWE)

  • CWE-798
    Use of Hard-coded Credentials