CVE-2014-6051: Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows rem

Q: How do I fix CVE-2014-6051?

enterprise linux server aus: mitigate or apply the listed mitigation; enterprise linux server eus: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2014-6051 being exploited?

CVE-2014-6051 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-2014-6051 affect?

CVE-2014-6051 affects enterprise linux server aus, enterprise linux server eus, fedora. Severity is high (CVSS 7.5). Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows remote VNC servers to cause a denial of service (crash) and possibly execute arbitrary code via an advertisement for a large screen s

Q: How urgent is CVE-2014-6051?

Priority 55/100. High severity; EPSS top 5%: very likely to be exploited; On your watchlist

This month

HIGH 7.5WATCHLISTMITIGATEMITIGATEMITIGATE

CVE-2014-6051 is a high-severity flaw (CVSS 7.5) affecting enterprise linux server aus, enterprise linux server eus, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows remote VNC servers to cause a denial of service (crash) and possibly execute arbitrary code via an advertisement for a large screen size, which triggers a heap-based buffer overflow.

Why this priority

High severity
EPSS top 5%: very likely to be exploited
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	8.3% (top 5%)
CISA exploited list	No
Weakness	CWE-189
Published	2014-09-30
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · fedoraproject · libvncserver · oracle · redhat

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

Am I affected?

Timeline

2014-09-30 16:55 UTCPublished CVE record published
2026-06-17 00:12 UTCUpdated Record last modified

redhat enterprise linux server aus MITIGATE

Affected: 6.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.5

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.

redhat enterprise linux server eus MITIGATE

Affected: 6.5.z

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.5.z

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.

fedoraproject fedora MITIGATE

Affected: 20 · 21

Fixed in: no fixed release known

Safe to downgrade to: a release before 20

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.

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.

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.

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.

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-2014-6051?

enterprise linux server aus: mitigate or apply the listed mitigation; enterprise linux server eus: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2014-6051 being exploited?

CVE-2014-6051 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-2014-6051 affect?

CVE-2014-6051 affects enterprise linux server aus, enterprise linux server eus, fedora. Severity is high (CVSS 7.5). Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows remote VNC servers to cause a denial of service (crash) and possibly execute arbitrary code via an advertisement for a large screen s

How urgent is CVE-2014-6051?

Priority 55/100. High severity; EPSS top 5%: very likely to be exploited; On your watchlist

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References

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