Debian LinuxOperating system · Debian
CVE-2018-20022
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedLibVNC before 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838 contains multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allows attacker to read stack memory and can be abuse for information disclosure. Combined with another vulnerability, it can be used to leak stack memory layout and in bypassing ASLR
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceLibVNC contains an improper initialization vulnerability (CWE-665) in VNC client code that allows uninitialized stack memory to be read and transmitted to an attacker. This information disclosure can reveal stack memory contents, and when combined with other vulnerabilities, can enable stack layout leaking and ASLR bypass.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Debian LinuxOperating system
= 8.0= 9.0
Ubuntu LinuxOperating system
= 14.04= 16.04= 18.04= 18.10< 0.9.12CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed LibVNC packagesRun `dpkg -l | grep -i vnc` (Debian/Ubuntu) or check for libvncserver libraries in /usr/lib/Affected if No LibVNC packages are found (not vulnerable because not installed)
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Determine LibVNC server versionRun `dpkg -l libvncserver0` or check the library file version with `strings /usr/lib/x86_64-linux-gnu/libvncserver.so.1 | grep -i version`Affected if Version is present and < 0.9.12 (compare against the affected ranges)
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Check for LibVNC client usageReview running processes for VNC client applications using libvncclient (look for vncviewer, remmina with VNC, or any custom app linking to libvncclient)Affected if A VNC client application using libvncclient is running and making outbound connections
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Inspect network connections for VNC trafficUse `ss -tunap` or `netstat -tunap` to look for active outbound VNC connections (typically port 5900+)Affected if Outbound VNC connections are active from a system with vulnerable libvncclient version < 0.9.12
A system is affected if it has LibVNC client (libvncclient) version < 0.9.12 installed AND is actively functioning as a VNC client making outbound connections, which could transmit uninitialized stack memory to a remote VNC server.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data0.9.12
Update LibVNC to the patched version beyond commit 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838, or apply the specific fix for the improper initialization issue in the VNC client code to prevent stack memory disclosure.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20022 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-20022 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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