{"id":"CVE-2026-7839","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-7839","generatedAt":"2026-10-28T03:23:15.994Z","title":"UltraVNC repeater through 1.8.2.2 initializes the HTTP administration server with a hardcoded default password.","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.","published":"2026-07-01T05:16:25.000Z","lastModified":"2026-10-25T17:10:00.000Z","status":"Modified","sourceIdentifier":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","cvss":{"version":"3.1","score":9.1,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-798"],"affected":["uvnc/ultravnc"],"epss":{"score":0.00655,"percentile":0.51095,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"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."},"changes":[],"references":[{"url":"https://github.com/ultravnc/UltraVNC","tags":["Product"],"source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"},{"url":"https://uvnc.com/","tags":["Product","Release Notes"],"source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"},{"url":"https://www.securin.io/zero-days/cve-2026-7839-hardcoded-default-admin-password-adminadmi2-ultravnc-repeater","source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-7839","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}