CVE-2019-8266

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-13. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

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

UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnection::Copybuffer function in VNC client code, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. User interaction is required to trigger these vulnerabilities. These vulnerabilities have been fixed in revision 1208.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: 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
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
85.2%
KEV
Not listed

Published

March 8, 2019

Last Modified

November 21, 2024

Advisory Details (1)

Auto-updated Jul 6, 2026
No patch confirmed yet.
generic

KLCERT-19-013: UltraVNC Access of Memory Location After End of Buffer | Kaspersky ICS CERT EN

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-013-ultravnc-access-of-memory-location-after-end-of-buffer/

Weakness Classification(3)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 43× 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. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 01:47 UTCEG score recompute
  3. 2026-07-22 22:29 UTCEG score recompute
  4. 2026-07-22 14:05 UTCEPSS rescore
  5. 2026-07-21 15:22 UTCEPSS rescore
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  25. 2026-07-07 13:43 UTCEPSS rescore
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  1. 2026-07-06 16:25 UTCEPSS rescore
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  7. 2026-07-01 15:03 UTCEPSS rescore
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  9. 2026-06-30 23:20 UTCEPSS rescore
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  21. 2026-06-21 14:54 UTCEPSS rescore
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  23. 2026-06-21 01:57 UTCEPSS rescore
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  25. 2026-06-19 19:23 UTCEPSS rescore
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  27. 2026-06-18 17:50 UTCEPSS rescore
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  31. 2026-06-15 17:46 UTCEPSS rescore
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  37. 2026-06-11 13:58 UTCEPSS rescore
  38. 2026-06-10 22:16 UTCEPSS rescore
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  40. 2026-06-10 13:19 UTCEPSS rescore
  41. 2026-06-08 14:15 UTCEPSS rescore
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  44. 2026-06-07 15:23 UTCEPSS rescore
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  46. 2026-06-06 13:45 UTCEPSS rescore
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  48. 2026-06-05 22:45 UTCEPSS rescore
  49. 2026-06-05 06:08 UTCEPSS rescore
  50. 2026-06-04 13:10 UTCEPSS rescore
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  52. 2026-06-02 20:11 UTCEPSS rescore
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  54. 2026-06-01 13:50 UTCEPSS rescore
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  56. 2026-05-31 22:29 UTCEPSS rescore
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  58. 2026-05-31 00:14 UTCEPSS rescore
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  60. 2026-05-29 13:42 UTCEPSS rescore
  61. 2026-05-28 13:43 UTCEPSS rescore
  62. 2026-05-28 13:43 UTCEPSS rescore
  63. 2026-05-27 21:57 UTCEG score recompute
  64. 2026-05-27 21:57 UTCGHSA enrichment
  65. 2026-05-27 13:39 UTCEPSS rescore
  66. 2026-05-27 13:38 UTCEPSS rescore
  67. 2026-05-26 13:42 UTCEPSS rescore
  68. 2026-05-26 07:17 UTCEPSS rescore
  69. 2026-05-26 07:17 UTCEPSS rescore
  70. 2026-05-26 07:17 UTCEPSS rescore
  71. 2026-05-24 16:47 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2019-8266?
CVE-2019-8266 is a critical vulnerability published on March 8, 2019. UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnection::Copybuffer function in VNC client code, which can potentially result in code execution. This attack appears to be exploitable via network connectivity. User interaction is…
When was CVE-2019-8266 disclosed?
CVE-2019-8266 was first published in the National Vulnerability Database on March 8, 2019, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2019-8266 actively exploited?
CVE-2019-8266 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 85.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2019-8266?
CVE-2019-8266 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2019-8266?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-8266, 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.

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