CVE-2026-7831

HIGHPre-NVD 7.67.6—
EchelonGraph scoreMEDIUM confidence

Score 7.6 from GitHub Security Advisory (severity: HIGH) published 2026-07-01. a secondary CVSS source baseline 7.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this week
7.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.6Exploit: None knownExposed: 0

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

UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer _dn[2024] and calls ReadString(_dn, 2024). ReadString writes the NUL terminator at buf[length], i.e., _dn[2024], one byte past the end of the stack buffer. A malicious VNC server can trigger this condition by advertising a desktop name of length 2024 in its ServerInit message. On release builds without stack canaries the single-byte NUL overwrite adjacent stack data. On builds with /GS stack protection the canary is corrupted and the process terminates, resulting in denial of service. User interaction (connecting the viewer to the malicious server) is required.

CVSS v3
7.6
EG Score
7.6(medium)
EG Risk
34(Track)
EG Risk 34/100SSVC: 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
Severity76% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
52%
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-2026-7831(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 22× in last 7d / 117× 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 194 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-7831?
CVE-2026-7831 is a high vulnerability published on July 1, 2026. UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer dn[2024] and calls ReadString(dn, 2024).…
When was CVE-2026-7831 disclosed?
CVE-2026-7831 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-2026-7831 actively exploited?
CVE-2026-7831 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 48.2% of all scored CVEs.
What is the CVSS score of CVE-2026-7831?
CVE-2026-7831 has a CVSS v3 base score of 7.6 (NVD).
How do I remediate CVE-2026-7831?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-7831, 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-2026-7831

Explore →

Is Your Infrastructure Affected by CVE-2026-7831?

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

Start Free Scan →Browse All CVEs