CVE-2026-7839

CRITICALPre-NVD 9.19.1
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.1Exploit: None knownExposed services: Not assessed

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

The CVE record's CNA (Securin) lists uvnc UltraVNC versions up to and including 1.8.2.2 as affected. No release containing a fix is confirmed on record.

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
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100

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 (value × EchelonGraph’s weight)
Severity91% × 45%
The EG Score, 9.1 of 10.
Exploitation0.7% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.7%
EPSS %ILE
49th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 1, 2026

Last Modified

July 9, 2026

Advisory Details (3)

Auto-updated Sep 16, 2026
No fix on record yet.
Web page

CVE-2026-7839: Hardcoded Default Admin Password | Securin

https://www.securin.io/zero-days/cve-2026-7839-hardcoded-default-admin-password-adminadmi2-ultravnc-repeater
Web page

Home - UltraVNC VNC OFFICIAL SITE, Remote Desktop Free Opensource

https://uvnc.com/
Web page

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 12× in last 7d / 45× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 96 of 432 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 4 repeat rows among the latest 100 are merged into the row they repeat. The 336 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  2. 2026-10-12 15:36 UTCEG score recompute
  3. 2026-10-12 05:25 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-10-11 19:22 UTCEG score recompute
  5. 2026-10-11 16:38 UTCEG score recompute
  6. 2026-10-11 13:57 UTCEG score recompute
  7. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  8. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  9. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  10. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  11. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  12. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  13. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  14. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  15. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  16. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  18. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  19. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  20. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  21. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  22. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  23. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  24. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  25. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 49th percentile
Show 71 more
  1. 2026-09-23 11:15 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  2. 2026-09-23 06:57 UTCEG score recompute
  3. 2026-09-23 06:57 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  4. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  5. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  6. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  7. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  8. 2026-09-18 10:51 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  9. 2026-09-18 06:37 UTCEG score recompute
  10. 2026-09-18 06:37 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  11. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  12. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  13. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  14. 2026-09-14 08:30 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  15. 2026-09-14 04:27 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  16. 2026-09-14 00:28 UTCEG score recompute
  17. 2026-09-14 00:28 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  18. 2026-09-13 13:09 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  19. 2026-09-13 09:10 UTCEG score recompute
  20. 2026-09-13 09:10 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  21. 2026-09-12 14:51 UTCEG score recompute
  22. 2026-09-12 14:51 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  23. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  24. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  25. 2026-09-06 14:28 UTCEG score recompute
  26. 2026-09-06 14:28 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  27. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.7% · 49th percentile
  28. 2026-09-06 02:57 UTCEG score recompute
  29. 2026-09-06 02:57 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  30. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  31. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  32. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  33. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  34. 2026-08-31 01:20 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  35. 2026-08-30 21:18 UTCEG score recompute
  36. 2026-08-30 21:18 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  37. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  38. 2026-08-30 17:18 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  39. 2026-08-30 13:18 UTCEG score recompute
  40. 2026-08-30 13:18 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  41. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  42. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  43. 2026-08-28 02:48 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  44. 2026-08-27 22:29 UTCEG score recompute
  45. 2026-08-27 22:29 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  46. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  47. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  48. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  49. 2026-08-25 05:03 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  50. 2026-08-25 01:03 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  51. 2026-08-24 21:03 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  52. 2026-08-24 15:00 UTCEG score recompute
  53. 2026-08-24 15:00 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  54. 2026-08-24 14:18 UTCEPSS rescoreEPSS 0.7% · 48th percentile
  55. 2026-08-24 10:58 UTCEG score recompute
  56. 2026-08-24 10:58 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  57. 2026-08-24 04:52 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  58. 2026-08-24 00:49 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  59. 2026-08-23 20:50 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  60. 2026-08-23 16:49 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  61. 2026-08-23 12:49 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  62. 2026-08-23 08:49 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  63. 2026-08-23 04:40 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  64. 2026-08-23 00:40 UTCEG score recompute
  65. 2026-08-23 00:40 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  66. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  67. 2026-08-22 20:08 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  68. 2026-08-22 15:29 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  69. 2026-08-22 11:27 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  70. 2026-08-22 07:27 UTCGHSA enrichmentGHSA-h7cc-6wq3-9h7x · GitHub severity CRITICAL · GitHub CVSS 9.1
  71. 2026-08-22 01:17 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-7839?
CVE-2026-7839 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-7839 published?
The CVE record for CVE-2026-7839 was published on July 1, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of July 9, 2026; the record at its source may have been updated since.
Is CVE-2026-7839 actively exploited?
CVE-2026-7839 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (49th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-7839?
CVE-2026-7839 has a CVSS base score of 9.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-7839?
No fix for CVE-2026-7839 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (Securin) lists uvnc UltraVNC versions up to and including 1.8.2.2 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-7839 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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

Explore →

Is Your Infrastructure Affected by CVE-2026-7839?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs