PT-2019-4940 · Ultravnc · Ultravnc

Published 2019-03-05 · Updated 2020-06-12 · CVE-2019-8266

Positive Technologies (AI Summary)

CVSS v3.1

10

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions UltraVNC revision 1207

Description The issue is related to improper usage of the ClientConnection::Copybuffer function in the VNC client code, which can result in out-of-bounds access and potentially allow code execution. This can be exploited via network connectivity, and user interaction is required to trigger the issue. The exploitation of this vulnerability may allow a remote attacker to execute arbitrary code.

Recommendations For UltraVNC revision 1207, update to revision 1208 to resolve the issue. As a temporary workaround, consider restricting network connectivity to minimize the risk of exploitation until the update can be applied.

Fix

Access of Memory Location After End of Buffer

Memory Corruption

Out of bounds Read

Weakness Enumeration

CWE-788

CWE-787

CWE-125

Related Identifiers

BDU:2020-01548

CVE-2019-8266

Affected Products

Ultravnc

References · 8

• https://bdu.fstec.ru/vul/2020-01548 · Security Note
• https://osv.dev/vulnerability/CVE-2019-8266 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2019-8266 · Security Note
• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-013-ultravnc-access-of-memory-location-after-end-of-buffer · Note
• https://us-cert.gov/ics/advisories/icsa-20-161-06 · Note
• https://download.schneider-electric.com/files?p_enDocType=Technical+leaflet&p_File_Name=SEVD-2019-225-05-TelevisGO_Security_Notification.pdf&p_Doc_Ref=SEVD-2019-225-05 · Note
• https://download.schneider-electric.com/files?p_enDocType=Technical+leaflet&p_File_Name=SEVD-2019-225-05-TelevisGO_Security_Notification.pdf&p_Doc_Ref=SEVD-2019-225-05 · Note
• https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf · Note