CVE-2016-3067
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 · uneditedCygwin before 2.5.0 does not properly handle updating permissions when changing users, which allows attackers to gain privileges.
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 · moderate confidenceCygwin before version 2.5.0 contains a privilege escalation vulnerability where permission updates are not properly handled during user identity changes. This allows authenticated attackers to gain elevated privileges by exploiting improper permission state management when switching between users.
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<= 2.4.1-1CVSS 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
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/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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Check if Cygwin is installedLook for the Cygwin DLL (cygwin1.dll) in the system, typically under C:\cygwin\bin\ or C:\cygwin64\bin\, or run 'cygcheck -c' to query installed Cygwin packagesAffected if Cygwin is not found on the system, so the vulnerability does not apply
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Determine the installed Cygwin versionRun 'cygcheck -c cygwin' from a Cygwin terminal or examine the version of cygwin1.dll by right-clicking the file and viewing Properties > DetailsAffected if The installed version is 2.4.1-1 or lower (any version before 2.5.0)
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Verify Cygwin user switching functionality is in useReview any scripts, services, or applications that leverage Cygwin's POSIX layer to switch between user identities (e.g., using 'su', 'sudo', or RunAs functionality through Cygwin)Affected if The environment uses Cygwin to switch between user identities or runs processes under different user contexts via Cygwin
The system is affected if Cygwin version 2.4.1-1 or lower is installed AND the environment uses Cygwin's user identity switching or permission-sensitive operations.
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.
dbcve · scopedUpgrade Cygwin to version 2.5.0 or later to obtain the corrected permission handling code.
Cygwin 2.5.0 or later
- 1. Check the current Cygwin version by running: uname -r or cygcheck -c cygwin
- 2. Download the Cygwin setup.exe from the official Cygwin website (cygwin.com)
- 3. Run the Cygwin installer and select the option to upgrade all packages
- 4. Alternatively, from an existing Cygwin terminal, run: setup-x86.exe (for 32-bit) or setup-x86_64.exe (for 64-bit)
- 5. Follow the installer prompts to complete the upgrade to Cygwin 2.5.0 or later
- 6. Verify the upgrade was successful by running: cygcheck -c cygwin
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 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 $1,936.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-3067 — 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-2016-3067 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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