CVE-2014-6052: The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not chec

Q: How do I fix CVE-2014-6052?

libvncserver: upgrade to newer than 0.9.9; solaris: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2014-6052 being exploited?

CVE-2014-6052 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2014-6052 affect?

CVE-2014-6052 affects libvncserver, solaris, debian linux. Severity is high (CVSS 7.5). The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain malloc return values, which allows remote VNC servers to cause a denial of service (application crash) or possibly execu

Q: How urgent is CVE-2014-6052?

Priority 60/100. High severity; EPSS top 6%: very likely to be exploited; Public exploit reference; On your watchlist

This week

HIGH 7.5WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2014-6052 is a high-severity flaw (CVSS 7.5) affecting libvncserver, solaris, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain malloc return values, which allows remote VNC servers to cause a denial of service (application crash) or possibly execute arbitrary code by specifying a large screen size in a (1) FramebufferUpdate, (2) ResizeFrameBuffer, or (3) PalmVNCReSizeFrameBuffer message.

Why this priority

High severity
EPSS top 6%: very likely to be exploited
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	6.8% (top 6%)
CISA exploited list	No
Weakness	CWE-20
Published	2014-12-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: canonical · debian · libvncserver · oracle

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2014-12-15 18:59 UTCPublished CVE record published
2026-06-17 00:12 UTCUpdated Record last modified

libvncserver libvncserver UPGRADE

Affected: <= 0.9.9

Fixed in: newer than 0.9.9

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libvncserver || rpm -q libvncserver || libvncserver --version

2. UPGRADE to newer than 0.9.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libvncserver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libvncserver

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

oracle solaris MITIGATE

Affected: 11.3

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.3

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

canonical ubuntu linux MITIGATE

Affected: 12.04 · 14.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 12.04

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2014-6052?

libvncserver: upgrade to newer than 0.9.9; solaris: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2014-6052 being exploited?

CVE-2014-6052 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2014-6052 affect?

CVE-2014-6052 affects libvncserver, solaris, debian linux. Severity is high (CVSS 7.5). The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain malloc return values, which allows remote VNC servers to cause a denial of service (application crash) or possibly execu

How urgent is CVE-2014-6052?

Priority 60/100. High severity; EPSS top 6%: very likely to be exploited; Public exploit reference; On your watchlist

Software pages

Ubuntu vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2026-32854 HIGH 7.5 UPGRADE LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilit
CVE-2026-32853 HIGH 8.1 UPGRADE LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerabili
CVE-2020-29260 HIGH 7.5 DOWNGRADE MITIGATE libvncclient v0.9.13 was discovered to contain a memory leak via the function rfbClientCleanup().
CVE-2020-25708 HIGH 7.5 DOWNGRADE MITIGATE A divide by zero issue was found to occur in libvncserver-0.9.12
CVE-2020-14405 MEDIUM 6.5 UPGRADE MITIGATE An issue was discovered in LibVNCServer before 0.9.13

References

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