CVE-2019-8263 — UltraVNC revision 1205 has stack-based buffer overflow vulnerability in VNC client code inside ShowConnInfo routine, which leads to a denial of service (DoS) condition

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MEDIUM

UltraVNC revision 1205 has stack-based buffer overflow vulnerability in VNC client code inside ShowConnInfo routine, which leads to a denial of service (DoS) condition

Published Mar 5, 2019

6.5

MEDIUM

CVSS 3.1

EPSS 2.48%

Description

UltraVNC revision 1205 has stack-based buffer overflow vulnerability in VNC client code inside ShowConnInfo routine, which leads to a denial of service (DoS) condition. This attack appear to be exploitable via network connectivity. User interaction is required to trigger this vulnerability. This vulnerability has been fixed in revision 1206.

Affected products

Vendor Kaspersky Lab Product UltraVNC Default
n/a
- Version
  1.2.2.3
  Status
  affected
  Constraints
  -

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor

Product

Default status

Versions

Kaspersky Lab

UltraVNC

n/a

Version	Status	Constraints
1.2.2.3	affected	-

Remediation

No remediation recorded yet.

Metrics

2.48% 0.02480

Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.

EPSS probability 0.02480

Score over time

2021–2026

EPSS v1
EPSS v5
EPSS v2
EPSS v3

Percentile over time

EPSS v1
EPSS v5
EPSS v2
EPSS v3

Table of values (13 key points)

Flat stretches are collapsed; showing up to 120 newest points.

Date	Score	Percentile	Model
Oct 1, 2026	2.48% (0.02480)	84.00th	v5 (v2026.06.15)
Jun 15, 2026	2.48% (0.02480)	82.44th	v5 (v2026.06.15)
Jul 20, 2024	0.81% (0.00815)	82.00th	v3 (v2023.03.01)
Feb 23, 2024	0.81% (0.00815)	81.29th	v3 (v2023.03.01)
Feb 8, 2024	0.69% (0.00695)	79.58th	v3 (v2023.03.01)
Mar 7, 2023	0.69% (0.00695)	77.12th	v3 (v2023.03.01)
Mar 6, 2023	1.11% (0.01108)	55.18th	v2 (v2022.01.01)
Apr 1, 2022	1.11% (0.01108)	51.54th	v2 (v2022.01.01)
Mar 31, 2022	8.87% (0.08874)	83.33th	v2 (v2022.01.01)
Jan 6, 2022	8.63% (0.08626)	85.39th	v1
Jan 5, 2022	2.06% (0.02061)	77.63th	v5 (v2026.06.15)
May 12, 2021	1.81% (0.01806)	0.00th	v1
Apr 14, 2021	1.29% (0.01294)	0.00th	v1

Weaknesses (2)

CWE-121

CWE-787

Out-of-bounds Write

References (7)

https://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdf
x_refsource_CONFIRM
https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf
x_refsource_CONFIRMThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-940818.pdf
x_refsource_CONFIRM
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-009-ultravnc-access-of-memory-location-after-end-of-buffer/
x_refsource_MISCNot ApplicableThird Party Advisory
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-010-ultravnc-stack-based-buffer-overflow/
x_refsource_MISCThird Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-11
x_refsource_MISC
https://www.us-cert.gov/ics/advisories/icsa-20-161-06
x_refsource_MISCThird Party AdvisoryUS Government Resource

Link	Providers	Tags
https://cert-portal.siemens.com/productcert/pdf/ssa-286838.pdf		x_refsource_CONFIRM
https://cert-portal.siemens.com/productcert/pdf/ssa-927095.pdf		x_refsource_CONFIRMThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-940818.pdf		x_refsource_CONFIRM
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-009-ultravnc-access-of-memory-location-after-end-of-buffer/		x_refsource_MISCNot ApplicableThird Party Advisory
https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-010-ultravnc-stack-based-buffer-overflow/		x_refsource_MISCThird Party Advisory
https://us-cert.cisa.gov/ics/advisories/icsa-21-131-11		x_refsource_MISC
https://www.us-cert.gov/ics/advisories/icsa-20-161-06		x_refsource_MISCThird Party AdvisoryUS Government Resource