CVE-2026-7839

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreHIGH confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-01. a secondary CVSS source baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.1
EG Score
9.1(high)
EPSS
24.5%
KEV
Not listed

Published

July 1, 2026

Last Modified

July 2, 2026

Advisory Details (2)

Auto-updated Jul 1, 2026
No patch confirmed yet.
generic

Home - UltraVNC VNC OFFICIAL SITE, Remote Desktop Free Opensource

https://uvnc.com/
generic

GitHub - ultravnc/UltraVNC: 👁️ UltraVNC Server, UltraVNC Viewer, UltraVNC Repeater and UltraVNC SC | Official repository: https://github.com/ultravnc/UltraVNC · GitHub

https://github.com/ultravnc/UltraVNC

Vendor Advisories for CVE-2026-7839(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 81× in last 7d / 81× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-07 01:34 UTCEG score recompute
  2. 2026-07-07 01:34 UTCGHSA enrichment
  3. 2026-07-06 21:31 UTCEG score recompute
  4. 2026-07-06 21:31 UTCGHSA enrichment
  5. 2026-07-06 17:32 UTCEG score recompute
  6. 2026-07-06 17:32 UTCGHSA enrichment
  7. 2026-07-06 16:27 UTCEPSS rescore
  8. 2026-07-06 16:27 UTCEPSS rescore
  9. 2026-07-06 13:31 UTCEG score recompute
  10. 2026-07-06 13:30 UTCGHSA enrichment
  11. 2026-07-06 09:29 UTCEG score recompute
  12. 2026-07-06 09:29 UTCGHSA enrichment
  13. 2026-07-06 05:29 UTCEG score recompute
  14. 2026-07-06 05:29 UTCGHSA enrichment
  15. 2026-07-06 02:23 UTCEPSS rescore
  16. 2026-07-06 02:23 UTCEPSS rescore
  17. 2026-07-06 01:29 UTCEG score recompute
  18. 2026-07-06 01:29 UTCGHSA enrichment
  19. 2026-07-05 21:29 UTCEG score recompute
  20. 2026-07-05 21:29 UTCGHSA enrichment
  21. 2026-07-05 17:29 UTCEG score recompute
  22. 2026-07-05 17:29 UTCGHSA enrichment
  23. 2026-07-05 13:29 UTCEG score recompute
  24. 2026-07-05 13:29 UTCGHSA enrichment
  25. 2026-07-05 09:28 UTCEG score recompute
Show 56 more
  1. 2026-07-05 09:28 UTCGHSA enrichment
  2. 2026-07-05 05:28 UTCEG score recompute
  3. 2026-07-05 05:28 UTCGHSA enrichment
  4. 2026-07-05 02:31 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-05 01:26 UTCEG score recompute
  7. 2026-07-05 01:26 UTCGHSA enrichment
  8. 2026-07-04 21:26 UTCEG score recompute
  9. 2026-07-04 21:26 UTCGHSA enrichment
  10. 2026-07-04 17:26 UTCEG score recompute
  11. 2026-07-04 17:26 UTCGHSA enrichment
  12. 2026-07-04 13:26 UTCEG score recompute
  13. 2026-07-04 13:26 UTCGHSA enrichment
  14. 2026-07-04 09:27 UTCEG score recompute
  15. 2026-07-04 09:26 UTCGHSA enrichment
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-04 06:31 UTCEPSS rescore
  18. 2026-07-04 05:27 UTCEG score recompute
  19. 2026-07-04 05:27 UTCGHSA enrichment
  20. 2026-07-04 01:24 UTCEG score recompute
  21. 2026-07-04 01:24 UTCGHSA enrichment
  22. 2026-07-03 21:24 UTCEG score recompute
  23. 2026-07-03 21:24 UTCGHSA enrichment
  24. 2026-07-03 17:25 UTCEG score recompute
  25. 2026-07-03 17:25 UTCGHSA enrichment
  26. 2026-07-03 13:24 UTCEG score recompute
  27. 2026-07-03 13:24 UTCGHSA enrichment
  28. 2026-07-03 09:25 UTCEG score recompute
  29. 2026-07-03 09:25 UTCGHSA enrichment
  30. 2026-07-03 05:26 UTCEG score recompute
  31. 2026-07-03 05:25 UTCGHSA enrichment
  32. 2026-07-03 01:23 UTCEG score recompute
  33. 2026-07-03 01:22 UTCGHSA enrichment
  34. 2026-07-02 21:22 UTCEG score recompute
  35. 2026-07-02 21:22 UTCGHSA enrichment
  36. 2026-07-02 17:23 UTCEG score recompute
  37. 2026-07-02 17:23 UTCGHSA enrichment
  38. 2026-07-02 13:23 UTCEG score recompute
  39. 2026-07-02 13:23 UTCGHSA enrichment
  40. 2026-07-02 09:23 UTCEG score recompute
  41. 2026-07-02 09:23 UTCGHSA enrichment
  42. 2026-07-02 05:23 UTCEG score recompute
  43. 2026-07-02 05:23 UTCGHSA enrichment
  44. 2026-07-02 01:23 UTCEG score recompute
  45. 2026-07-02 01:23 UTCGHSA enrichment
  46. 2026-07-01 21:19 UTCEG score recompute
  47. 2026-07-01 21:19 UTCGHSA enrichment
  48. 2026-07-01 17:19 UTCEG score recompute
  49. 2026-07-01 17:19 UTCGHSA enrichment
  50. 2026-07-01 15:07 UTCEPSS rescore
  51. 2026-07-01 13:20 UTCEG score recompute
  52. 2026-07-01 13:20 UTCGHSA enrichment
  53. 2026-07-01 09:21 UTCEG score recompute
  54. 2026-07-01 09:21 UTCGHSA enrichment
  55. 2026-07-01 05:21 UTCEG score recompute
  56. 2026-07-01 05:20 UTCNVD updatefirst tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-7839?
CVE-2026-7839 is a critical vulnerability published on July 1, 2026. 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 strcpys(savedpassword, 64,…
When was CVE-2026-7839 disclosed?
CVE-2026-7839 was first published in the National Vulnerability Database on July 1, 2026, with the most recent update on July 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-7839 actively exploited?
CVE-2026-7839 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 24.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-7839?
CVE-2026-7839 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-7839?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-7839, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-7839

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