CVE-2017-18922: Buffer Overflow

Published Jun 30, 2020
·
Updated

It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.

Other sources

libvncserver container a heap-based buffer overflow within the websocket decoding functionality, which can be exploited by a malicious attacker to overwrite a function pointer.

Patch: https://github.com/LibVNC/libvncserver/commit/aac95a9dcf4bbba87b76c72706c3221a842ca433

Red Hat

Affected Software

35 affected componentsFixes available
redhat/libvncserver<0.9.12
0.9.12
Libvncserver Project Libvncserver<0.9.12
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=19.10
Canonical Ubuntu Linux=20.04
openSUSE Leap=15.1
openSUSE Leap=15.2
Fedoraproject Fedora=31
Fedoraproject Fedora=32
All of the following
Siemens Simatic Itc1500 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1500
All of the following
Siemens Simatic Itc1500 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1500 Pro
All of the following
Siemens Simatic Itc1900 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1900
All of the following
Siemens Simatic Itc1900 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1900 Pro
All of the following
Siemens Simatic Itc2200 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc2200
All of the following
Siemens Simatic Itc2200 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc2200 Pro
Siemens Simatic Itc1500 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1500
Siemens Simatic Itc1500 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1500 Pro
Siemens Simatic Itc1900 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1900
Siemens Simatic Itc1900 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc1900 Pro
Siemens Simatic Itc2200 Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc2200
Siemens Simatic Itc2200 Pro Firmware>=3.0.0.0<3.2.1.0
Siemens Simatic Itc2200 Pro
debian/libvncserver
0.9.13+dfsg-2+deb11u10.9.14+dfsg-1+deb12u10.9.15+dfsg-1+deb13u10.9.15+dfsg-6

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/libvncserver to a version that resolves this vulnerability.

    Fixed in 0.9.12
  2. Upgrade

    Upgrade debian/libvncserver to a version that resolves this vulnerability.

    Fixed in 0.9.13+dfsg-2+deb11u1Fixed in 0.9.14+dfsg-1+deb12u1Fixed in 0.9.15+dfsg-1+deb13u1Fixed in 0.9.15+dfsg-6
  3. Upgrade

    Upgrade LibVNCServer (libvncserver) to a version that resolves this vulnerability.

    Fixed in 0.9.12Patch aac95a9dcf4bbba87b76c72706c3221a842ca433

Event History

Jun 30, 2020
CVE Published
via MITRE·11:00 AM
Data Sourced
via MITRE·11:00 AM
Description
Data Sourced
via NVD·11:15 AM
RemedyDescriptionSeverityWeaknessAffected Software
Feb 18, 2026
Data Sourced
via Ubuntu·08:00 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·08:00 PM
Description
Jul 5, 2026
Data Sourced
via Debian·02:52 AM
DescriptionAffected Software
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Frequently Asked Questions

1

What is CVE-2017-18922?

CVE-2017-18922 is a vulnerability in LibVNCServer that allows a malicious attacker to cause a heap-based buffer overflow by sending specially crafted WebSocket frames.

2

How severe is CVE-2017-18922?

CVE-2017-18922 has a severity rating of 9.8 out of 10, making it a critical vulnerability.

3

Which software versions are affected by CVE-2017-18922?

The affected software versions for CVE-2017-18922 include LibVNCServer prior to 0.9.12.

4

How can I fix CVE-2017-18922?

To fix CVE-2017-18922, you should update LibVNCServer to version 0.9.12 or later.

5

Where can I find more information about CVE-2017-18922?

More information about CVE-2017-18922 can be found on the CVE website at https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-18922.

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