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CVE-2018-20748· NVD / CVE Program· CNA mitre

LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c.

LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jan 30, 2019
Updated
Jun 16, 2026
EPSS
3.3% · 88th percentile
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Report tools

JSON

Action score

40

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.3%

Affected systems

VendorProduct
libvnc projectlibvncserver
debiandebian linux
canonicalubuntu linux
siemenssimatic itc1500 firmware
siemenssimatic itc1500
siemenssimatic itc1500 pro firmware
siemenssimatic itc1500 pro
siemenssimatic itc1900 firmware
siemenssimatic itc1900
siemenssimatic itc1900 pro firmware
siemenssimatic itc1900 pro
siemenssimatic itc2200 firmware

and 3 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical ubuntu linux14.04
  • canonical ubuntu linux16.04
  • canonical ubuntu linux18.04
  • canonical ubuntu linux18.10
  • debian debian linux8.0
  • libvnc project libvncserverbefore 0.9.12
  • siemens simatic itc1500 firmware3.0.0.0 and later · before 3.2.1.0
  • siemens simatic itc1500 pro firmware3.0.0.0 and later · before 3.2.1.0
  • siemens simatic itc1900 firmware3.0.0.0 and later · before 3.2.1.0
  • siemens simatic itc1900 pro firmware3.0.0.0 and later · before 3.2.1.0
  • siemens simatic itc2200 firmware3.0.0.0 and later · before 3.2.1.0
  • siemens simatic itc2200 pro firmware3.0.0.0 and later · before 3.2.1.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12libvncserverbefore 0.9.11+dfsg-1.30.9.11+dfsg-1.3
Debian:12veyonbefore 4.1.7+repack1-14.1.7+repack1-1
Debian:8italcbefore 1:2.0.2+dfsg1-2+deb8u11:2.0.2+dfsg1-2+deb8u1
Debian:8libvncserverbefore 0.9.9+dfsg2-6.1+deb8u50.9.9+dfsg2-6.1+deb8u5
openSUSE:Leap 15.0LibVNCServerbefore 0.9.10-lp150.3.6.10.9.10-lp150.3.6.1
SUSE:Linux Enterprise Module for Package Hub 15LibVNCServerbefore 0.9.10-4.6.10.9.10-4.6.1
SUSE:Linux Enterprise Software Development Kit 11 SP4LibVNCServerbefore 0.9.1-160.9.10.9.1-160.9.1
SUSE:OpenStack Cloud 7LibVNCServerbefore 0.9.9-17.11.10.9.9-17.11.1

Other highest-scoring records for the same primary product.

  • CVE-2018-15127LibVNC before commit 502821828ed00b4a2c4bef90683d0fd88ce495de contains heap out-of-bound write vulnerability in server code of file transfer
    44Plan
  • CVE-2018-15126LibVNC before commit 73cb96fec028a576a5a24417b57723b55854ad7b contains heap use-after-free vulnerability in server code of file transfer ext
    43Plan
  • CVE-2018-20020LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client
    42Plan
  • CVE-2018-20019LibVNC before commit a83439b9fbe0f03c48eb94ed05729cb016f8b72f contains multiple heap out-of-bound write vulnerabilities in VNC client code t
    42Plan
  • CVE-2019-20788libvncclient/cursor.c in LibVNCServer through 0.9.12 has a HandleCursorShape integer overflow and heap-based buffer overflow via a large hei
    40Plan
  • CVE-2018-20750LibVNC through 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c.
    40Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:italc1:2.0.2+dfsg1-2+deb8u1 · Debian:8Package registry (OSV)
debian:libvncserver0.9.11+dfsg-1.3 · Debian:12Package registry (OSV)
debian:veyon4.1.7+repack1-1 · Debian:12Package registry (OSV)
opensuse:LibVNCServer0.9.10-lp150.3.6.1 · openSUSE:Leap 15.0Package registry (OSV)
suse:LibVNCServer0.9.10-4.6.1 · SUSE:Linux Enterprise Module for Package Hub 15Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

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References

All records