What is CVE-2026-7839?

CVE-2026-7839 is a critical-severity vulnerability in Uvnc Ultravnc, classified under Use of Hard-coded Credentials. CVSS score: 9.1/10. Published 2026-07-01.

How severe is CVE-2026-7839?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Vulnerability in Uvnc Ultravnc

CVE-2026-7839

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…

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Uvnc Ultravnc — versions 0

Weakness classification (CWE)

CWE-798 — Use of Hard-coded Credentials

References

33c584b5-0579-4c06-b2a0-8d8329fcab9c (vendor-advisory)
33c584b5-0579-4c06-b2a0-8d8329fcab9c (product)

Frequently asked questions

What is CVE-2026-7839?: CVE-2026-7839 is a critical-severity vulnerability in Uvnc Ultravnc, classified under Use of Hard-coded Credentials. CVSS score: 9.1/10. Published 2026-07-01.
How severe is CVE-2026-7839?: Critical severity. CVSS v3 base score is 9.1 out of 10.