No exploitation reportedFix available

CVE-2019-8261

Q: Is CVE-2019-8261 actively exploited?

Active exploitation of CVE-2019-8261 has not been confirmed. Its EPSS score was 2.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2019-8261?

CVE-2019-8261 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2019-03-05
Fixed in1.2.2.3
WeaknessCWE-125

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

UltraVNC revision 1199 has a out-of-bounds read vulnerability in VNC code inside client CoRRE decoder, caused by multiplication overflow. This attack appears to be exploitable via network connectivity. This vulnerability has been fixed in revision 1200.

Timeline

dates in UTC

2019-03-0515:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-8261?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-8261?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Uvnc ultravnc

Branch	Affected	Fixed in	Source
1.2	< 1.2.2.3	1.2.2.3	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-21-131-04 CISA8 known affected
Siemens SINAMICS Medium Voltage Products Remote Access (Update B)
SINAMICS GH150 · SINAMICS GL150 (with option X30) · SINAMICS GM150 (with option X30) · +5 more
ICSA-21-131-11 CISA4 known affected
Siemens SIMATIC UltraVNC HMI WinCC Products
SIMATIC HMI Comfort Outdoor Panels 7" & 15" (incl. SIPLUS variants) · SIMATIC HMI Comfort Panels 4" - 22" (incl. SIPLUS variants) · SIMATIC HMI KTP Mobile Panels KTP400F, KTP700, KTP700F, KTP900 and KTP900F · +1 more
ICSA-20-161-06 CISA3 known affected
Siemens SINUMERIK
Siemens SINUMERIK Access MyMachine /P2P: All versions < V4.8 · Siemens SINUMERIK PCU base Win10 software /IPC: All versions < V14.00 · Siemens SINUMERIK PCU base Win7 software /IPC: All versions < V12.01 HF4

Full record on NVD

Fix

Update Uvnc ultravnc to 1.2.2.3
Vendor fix CISA ICSA-21-131-11 · 3 productsUpdate SIMATIC WinCC (TIA Portal) to V16 Update 4 or later version, and then update panel to V16 Update 4 or later version
Vendor fix CISA ICSA-21-131-11 · 1 productUpdate to V16 Update 4 or later version
Vendor fix CISA ICSA-20-161-06 · 1 productUpdate to V4.8
Vendor fix CISA ICSA-20-161-06 · 1 productUpdate to V14.00
Vendor fix CISA ICSA-20-161-06 · 1 productUpdate to V12.01 HF4
Mitigation from the vendor CISA ICSA-21-131-04 · 1 productAs only SIMATIC HMI image versions < V16 Update 4 are affected, please update the HMI Panel image as included in your installation of SINAMICS GH150 to V16 Update 4 or later version

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.09.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
CNAweakness (CWE)CWE-125read 2026-10-23
NVDweakness (CWE)CWE-125read 2026-10-23
FIRST EPSSEPSS score2.2 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2019-03-05
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2019-8261?

Is CVE-2019-8261 actively exploited?

Active exploitation of CVE-2019-8261 has not been confirmed. Its EPSS score was 2.2% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-8261?

CVE-2019-8261 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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