CVE-2026-7839
UltraVNC repeater through 1.8.2.2 initializes the HTTP administration server with a hardcoded default password.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.66%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.66% probability · 49th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-798
- Affected
- uvnc/ultravnc
- Source
- 33c584b5-0579-4c06-b2a0-8d8329fcab9c
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.