GuacamoleApplication · Apache
CVE-2017-3158
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 · uneditedA race condition in Guacamole's terminal emulator in versions 0.9.5 through 0.9.10-incubating could allow writes of blocks of printed data to overlap. Such overlapping writes could cause packet data to be misread as the packet length, resulting in the remaining data being written beyond the end of a statically-allocated buffer.
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 confidenceA race condition in Guacamole's terminal emulator allows overlapping writes of printed data blocks, causing packet length data to be misread. This results in a heap/stack-based buffer overflow when data is written beyond the bounds of a statically-allocated buffer.
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
GuacamoleApplication
<= 0.9.9= 0.9.10-incubatingCVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
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 Guacamole installation versionLocate and inspect the Guacamole package or application version information using your system's package manager, configuration files, or the Guacamole web interface about/pageAffected if The installed version is 0.9.9 or earlier, or is 0.9.10-incubating
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Verify terminal emulator component is in useDetermine if the Guacamole terminal emulator (for VNC, RDP, or SSH connections) is actively configured or accessible to usersAffected if The terminal emulator feature is enabled and users can establish remote desktop/terminal connections through Guacamole
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Confirm network-accessible Guacamole serviceCheck if the Guacamole client or server component is exposed over the network, allowing external connections to the terminal emulatorAffected if The Guacamole service accepts remote connections enabling the race condition to be triggered by concurrent sessions
You are affected if your installed Apache Guacamole version is 0.9.9 or earlier, or 0.9.10-incubating, and the terminal emulator component is actively in use.
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 dataUpgrade to Guacamole version 0.9.11 or later, which contains the fix for the race condition and proper synchronization in the terminal emulator component.
Fix this in Guacamole
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-3158 — 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-2017-3158 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
- No weaponised exploit code, or anything meant to cause harm
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