PatchTheCVECVE-2018-7225: An issue was discovered in LibVNCServer through 0.9.11
73
This week
CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE
CVE-2018-7225 is a critical-severity flaw (CVSS 9.8) affecting libvncserver, debian linux, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An issue was discovered in LibVNCServer through 0.9.11. rfbProcessClientNormalMessage() in rfbserver.c does not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact (e.g., an integer overflow) via specially crafted VNC packets.
Why this priority
- Critical severity
- EPSS top 7%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 6.1% (top 7%) |
| CISA exploited list | No |
| Weakness | CWE-190 |
| Published | 2018-02-19 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
libvncserver project libvncserver UPGRADE
Affected: <= 0.9.11
Fixed in: newer than 0.9.11
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 0.9.11 (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 · 8.0 · 9.0
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: 14.04 · 16.04 · 17.10
Fixed in: no fixed release known
Safe to downgrade to: a release before 14.04
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.
redhat enterprise linux desktop 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.
redhat enterprise linux server 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.
redhat enterprise linux server aus MITIGATE
Affected: 7.6
Fixed in: no fixed release known
Safe to downgrade to: a release before 7.6
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.
Exact fixes by distribution
A distro patch exists: prefer upgrading over downgrading.
Fedora 46 · shotcut · FIXED · 26.10.30-1.fc46 · FEDORA-2026-7787c7fc2d · source
sudo dnf upgrade --advisory=FEDORA-2026-7787c7fc2d
Ubuntu 20.04 · libvncserver · FIXED · 0.9.11+dfsg-1ubuntu0.1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1ubuntu0.1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 22.04 · libvncserver · FIXED · 0.9.11+dfsg-1ubuntu1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.04 · libvncserver · FIXED · 0.9.11+dfsg-1ubuntu1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 24.10 · libvncserver · FIXED · 0.9.11+dfsg-1ubuntu1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Ubuntu 25.04 · libvncserver · FIXED · 0.9.11+dfsg-1ubuntu1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1ubuntu1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · libvncserver · FIXED · 0.9.11+dfsg-1.1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1.1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · libvncserver · FIXED · 0.9.11+dfsg-1.1
sudo apt update && sudo apt install --only-upgrade libvncserver
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' libvncserver)" ge "0.9.11+dfsg-1.1" && echo PATCHED || echo STILL-VULNERABLE
Debian 12 · tightvnc · FIXED · 1:1.3.9-9.1
sudo apt update && sudo apt install --only-upgrade tightvnc
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tightvnc)" ge "1:1.3.9-9.1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · tightvnc · FIXED · 1:1.3.9-9.1
sudo apt update && sudo apt install --only-upgrade tightvnc
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tightvnc)" ge "1:1.3.9-9.1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 · libvncserver · FIXED · libvncserver-0.9.9-12.el7_5
sudo dnf upgrade --advisory=RHSA-2018:1055
rpm -q libvncserver
RHEL 6 · libvncserver · DEFERRED
Alpine 3.20 · libvncserver · FIXED · libvncserver-0.9.11-r2
apk add --upgrade libvncserver
apk info -v libvncserver
Alpine 3.21 · libvncserver · FIXED · libvncserver-0.9.11-r2
apk add --upgrade libvncserver
apk info -v libvncserver
Alpine 3.22 · libvncserver · FIXED · libvncserver-0.9.11-r2
apk add --upgrade libvncserver
apk info -v libvncserver
Alpine 3.23 · libvncserver · FIXED · libvncserver-0.9.11-r2
apk add --upgrade libvncserver
apk info -v libvncserver
sudo yum update --advisory=ALAS2-2018-1012
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: usn.ubuntu.com/4587-1/
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.
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-2018-7225?
libvncserver: upgrade to newer than 0.9.11; debian linux: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2018-7225 being exploited?
CVE-2018-7225 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-2018-7225 affect?
CVE-2018-7225 affects libvncserver, debian linux, ubuntu linux. Severity is critical (CVSS 9.8). An issue was discovered in LibVNCServer through 0.9.11. rfbProcessClientNormalMessage() in rfbserver.c does not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact
How urgent is CVE-2018-7225?
Priority 73/100. Critical severity; EPSS top 7%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; 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