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
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)
EG Risk
56(Track)
EG Risk 56/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
34.8%
KEV
Not listed

Published

July 1, 2026

Last Modified

July 9, 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 11× in last 7d / 131× 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.

Showing the most recent 100 of 131 total refreshes for this CVE.

  1. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-23 14:18 UTCEPSS rescore
  3. 2026-07-23 03:23 UTCEG score recompute
  4. 2026-07-22 14:08 UTCEPSS rescore
  5. 2026-07-22 14:08 UTCEPSS rescore
  6. 2026-07-21 15:25 UTCEPSS rescore
  7. 2026-07-21 15:25 UTCEPSS rescore
  8. 2026-07-20 17:08 UTCEPSS rescore
  9. 2026-07-19 14:31 UTCEPSS rescore
  10. 2026-07-19 02:29 UTCEPSS rescore
  11. 2026-07-18 10:04 UTCEPSS rescore
  12. 2026-07-17 06:32 UTCGHSA enrichment
  13. 2026-07-17 02:31 UTCGHSA enrichment
  14. 2026-07-16 22:31 UTCGHSA enrichment
  15. 2026-07-16 18:31 UTCGHSA enrichment
  16. 2026-07-16 17:03 UTCEPSS rescore
  17. 2026-07-16 14:27 UTCGHSA enrichment
  18. 2026-07-16 10:28 UTCGHSA enrichment
  19. 2026-07-16 06:28 UTCGHSA enrichment
  20. 2026-07-16 02:18 UTCGHSA enrichment
  21. 2026-07-15 22:18 UTCGHSA enrichment
  22. 2026-07-15 18:19 UTCGHSA enrichment
  23. 2026-07-15 16:57 UTCEPSS rescore
  24. 2026-07-15 14:19 UTCGHSA enrichment
  25. 2026-07-15 10:16 UTCGHSA enrichment
Show 75 more
  1. 2026-07-15 06:14 UTCGHSA enrichment
  2. 2026-07-15 02:13 UTCGHSA enrichment
  3. 2026-07-15 02:00 UTCEPSS rescore
  4. 2026-07-14 22:13 UTCGHSA enrichment
  5. 2026-07-14 18:14 UTCGHSA enrichment
  6. 2026-07-14 14:14 UTCGHSA enrichment
  7. 2026-07-14 10:13 UTCGHSA enrichment
  8. 2026-07-14 06:12 UTCGHSA enrichment
  9. 2026-07-14 02:09 UTCGHSA enrichment
  10. 2026-07-13 22:31 UTCEPSS rescore
  11. 2026-07-13 22:09 UTCGHSA enrichment
  12. 2026-07-13 18:09 UTCGHSA enrichment
  13. 2026-07-13 14:09 UTCGHSA enrichment
  14. 2026-07-13 10:08 UTCGHSA enrichment
  15. 2026-07-13 06:13 UTCEPSS rescore
  16. 2026-07-13 05:56 UTCGHSA enrichment
  17. 2026-07-13 01:56 UTCGHSA enrichment
  18. 2026-07-12 21:56 UTCGHSA enrichment
  19. 2026-07-12 17:56 UTCGHSA enrichment
  20. 2026-07-12 13:56 UTCGHSA enrichment
  21. 2026-07-12 09:55 UTCGHSA enrichment
  22. 2026-07-12 05:55 UTCGHSA enrichment
  23. 2026-07-12 05:46 UTCEPSS rescore
  24. 2026-07-12 01:55 UTCGHSA enrichment
  25. 2026-07-11 21:55 UTCGHSA enrichment
  26. 2026-07-11 17:55 UTCGHSA enrichment
  27. 2026-07-11 13:55 UTCGHSA enrichment
  28. 2026-07-11 09:55 UTCGHSA enrichment
  29. 2026-07-11 08:27 UTCEPSS rescore
  30. 2026-07-11 05:55 UTCGHSA enrichment
  31. 2026-07-11 01:55 UTCGHSA enrichment
  32. 2026-07-10 21:54 UTCGHSA enrichment
  33. 2026-07-10 17:54 UTCGHSA enrichment
  34. 2026-07-10 13:53 UTCGHSA enrichment
  35. 2026-07-10 09:52 UTCGHSA enrichment
  36. 2026-07-10 05:52 UTCGHSA enrichment
  37. 2026-07-10 01:51 UTCGHSA enrichment
  38. 2026-07-09 21:52 UTCGHSA enrichment
  39. 2026-07-09 19:10 UTCEPSS rescore
  40. 2026-07-09 19:10 UTCEPSS rescore
  41. 2026-07-09 17:52 UTCGHSA enrichment
  42. 2026-07-09 13:52 UTCGHSA enrichment
  43. 2026-07-09 09:53 UTCGHSA enrichment
  44. 2026-07-09 05:53 UTCGHSA enrichment
  45. 2026-07-09 01:53 UTCGHSA enrichment
  46. 2026-07-08 21:53 UTCGHSA enrichment
  47. 2026-07-08 17:53 UTCGHSA enrichment
  48. 2026-07-08 15:16 UTCEPSS rescore
  49. 2026-07-08 15:16 UTCEPSS rescore
  50. 2026-07-08 13:49 UTCGHSA enrichment
  51. 2026-07-08 09:46 UTCGHSA enrichment
  52. 2026-07-08 05:47 UTCGHSA enrichment
  53. 2026-07-08 01:44 UTCGHSA enrichment
  54. 2026-07-07 21:44 UTCGHSA enrichment
  55. 2026-07-07 17:44 UTCGHSA enrichment
  56. 2026-07-07 13:46 UTCEPSS rescore
  57. 2026-07-07 13:46 UTCEPSS rescore
  58. 2026-07-07 13:35 UTCGHSA enrichment
  59. 2026-07-07 09:35 UTCGHSA enrichment
  60. 2026-07-07 05:35 UTCGHSA enrichment
  61. 2026-07-07 01:34 UTCGHSA enrichment
  62. 2026-07-06 21:31 UTCGHSA enrichment
  63. 2026-07-06 17:32 UTCGHSA enrichment
  64. 2026-07-06 16:27 UTCEPSS rescore
  65. 2026-07-06 16:27 UTCEPSS rescore
  66. 2026-07-06 13:30 UTCGHSA enrichment
  67. 2026-07-06 09:29 UTCGHSA enrichment
  68. 2026-07-06 05:29 UTCGHSA enrichment
  69. 2026-07-06 02:23 UTCEPSS rescore
  70. 2026-07-06 02:23 UTCEPSS rescore
  71. 2026-07-06 01:29 UTCGHSA enrichment
  72. 2026-07-05 21:29 UTCGHSA enrichment
  73. 2026-07-05 17:29 UTCGHSA enrichment
  74. 2026-07-05 13:29 UTCGHSA enrichment
  75. 2026-07-05 09:28 UTCGHSA enrichment

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 9, 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 34.8% 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

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