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Full vulnerability report · 2025
CVE-2019-15690High confidence

LibVNCServer 0.9.12 release and earlier contains heap buffer overflow vulnerability within the HandleCursorShape() function in libvncclient/cursor.c

LibVNC · LibVNCServer

8.8HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SSA-390195 · CSAF 2.0 · revision 1 · finalSiemens ProductCERTSSA-390195: LibVNC Vulnerabilities in SIMATIC ITC Products
6 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • SIMATIC ITC1500 V3
  • SIMATIC ITC1500 V3 PRO
  • SIMATIC ITC1900 V3
  • SIMATIC ITC1900 V3 PRO
  • SIMATIC ITC2200 V3
  • SIMATIC ITC2200 V3 PRO
Summary
A flaw was found in libvncserver. An integer overflow within the HandleCursorShape() function can be exploited to cause a heap-based buffer overflow by tricking a user or application using libvncserver to connect to an unstrusted server and subsequently send cursor shapes with specially crafted dimensions. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Remediation
Update to V3.2.1.0 or later version
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2019-6629

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

LibVNCServer 0.9.12 release and earlier contains heap buffer overflow vulnerability within the HandleCursorShape() function in libvncclient/cursor.c. An attacker sends cursor shapes with specially crafted dimensions, which can result in remote code execution.

What

LibVNCServer 0.9.12 release and earlier contains heap buffer overflow vulnerability within the HandleCursorShape() function in libvncclient/cursor.c. An attacker sends cursor shapes with specially crafted dimensions, which can result in remote code execution.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

What

LibVNCServer 0.9.12 release and earlier contains heap buffer overflow vulnerability within the HandleCursorShape() function in libvncclient/cursor.c. An attacker sends cursor shapes with specially crafted dimensions, which can result in remote code execution.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Heap-based Buffer Overflow → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-122 ↗

CWE-122: Heap-based Buffer Overflow. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-122
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

CERT-FR · French · CERTFR-2021-AVI-949Multiples vulnérabilités dans les produits Siemens

/pdf/ssa-802578.pdf Référence CVE CVE-2017-18922 https://www.cve.org/CVERecord?id=CVE-2017-18922 Référence CVE CVE-2018-15127 https://www.cve.org/CVERecord?id=CVE-2018-15127 Référence CVE CVE-2018-20019 https://www.cve.org/CVERecord?id=CVE-2018-20019 Référence CVE CVE-2018-20748 https://www.cve.org/CVERecord?id=CVE-2018-20748 Référence CVE CVE-2018-20749 https://www.cve.org/CVERecord?id=CVE-2018-20749 Référence CVE CVE-2018-20750 https://www.cve.org/CVERecord?id=CVE-2018-20750 Référence CVE CVE-2018-21247 https://www.cve.org/CVERecord?id=CVE-2018-21247 Référence CVE CVE-2019-15681 https://www.cve.org/CVERecord?id=CVE-2019-15681 Référence CVE CVE-2019-15690 https://www.cve.org/CVERecord?id=CVE-2019-15690 Référence CVE CVE-2019-20788 https://www.cve.org/CVERecord?id=CVE-2019-20788 Référence CVE CVE-2019-20839 https://www.cve.org/CVERecord?id=CVE-2019-20839 Référence CVE CVE-2019-20840 https://www.cve.org/CVERecord?id=CVE-2019-20840 Référence CVE CVE-2020-14396 https://www.cve.org/CVERecord?id=CVE-2020-14396 Référence CVE CVE-2020-14397 https://www.cve.org/CVERecord?id=CVE-2020-14397 Référence CVE CVE-2020-14398 https://www.cve.org/CVERecord?id=CVE-2020-14398 Référence CVE CVE-2020-14401 https://www.cve.org/CVERecord?id=CVE-2020-14401 Référence CVE CVE-2020-14402 https://www.cve.org/CVERecord?id=

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
SIMATIC ITC1500 V3; SIMATIC ITC1500 V3 PRO; SIMATIC ITC1900 V3; SIMATIC ITC1900 V3 PRO; SIMATIC ITC2200 V3; SIMATIC ITC2200 V3 PRO
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Update to V3.2.1.0 or later version
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 24 Jan 2025 · Last source change 24 Jan 2025, 18:22 UTC · CWE-122 · Heap-based Buffer Overflow

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2019-6629
Product sourceVendor CSAF · Siemens ProductCERT
Remediation sourceVendor CSAF · Siemens ProductCERT
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2019-6629↗Vendor CSAF · Siemens ProductCERT↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2019-15690 · cve.blacktree.nl