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Fencer Intel
critical 9.8

CVE-2019-8266 json

UltraVNC revision 1207 has multiple out-of-bounds access vulnerabilities connected with improper usage of ClientConnection::Copybuffer func…

published 7y ago modified 4mo ago also EUVD-2019-17664

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.8%
EPSS 2.8% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

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.

Patch / fix

  • uvnc ultravnc 1.2.2.3

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-20-161-06 updated cvss 9.8

Siemens SINUMERIK

  • Siemens SINUMERIK Access MyMachine /P2P <V4.8
    affected: fixed in V4.8, mitigation
  • Siemens SINUMERIK PCU base Win7 software /IPC <V12.01_HF4
    affected: fixed in V12.01, mitigation
  • Siemens SINUMERIK PCU base Win10 software /IPC <V14.00
    affected: fixed in V14.00, mitigation

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

2.84% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Affected products

  • Kaspersky Lab UltraVNC

Classification

Weakness
  • CWE-788 Access of Memory Location After End of Buffer
  • CWE-125 Out-of-bounds Read
  • CWE-787 Out-of-bounds Write

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.