CurlApplication · Haxx
CVE-2016-4802
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 · uneditedMultiple untrusted search path vulnerabilities in cURL and libcurl before 7.49.1, when built with SSPI or telnet is enabled, allow local users to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse (1) security.dll, (2) secur32.dll, or (3) ws2_32.dll in the application or current working directory.
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 confidencecURL and libcurl before 7.49.1, when built with SSPI or telnet support, suffer from DLL hijacking vulnerabilities. The application loads DLLs (security.dll, secur32.dll, ws2_32.dll) using relative paths from the current working directory or application directory without secure search path ordering. Local attackers can place malicious DLLs with these names in directories where the application runs, causing arbitrary code execution upon DLL injection.
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
CurlApplication
<= 7.49.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/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 the installed cURL versionRun 'curl --version' or check libcurl version programmaticallyAffected if The version reported is 7.49.0 or earlier (any version <= 7.49.0)
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Confirm Windows platformVerify the operating system is Windows - DLL hijacking via relative path loading is Windows-specificAffected if Running on Windows (Linux/macOS are not affected by this specific DLL hijacking flaw)
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Determine if SSPI or telnet support is enabledRun 'curl --version' and examine the feature list for 'SSPI' or 'telnet' keywords, or check the build configuration if availableAffected if The build includes SSPI or telnet support - these features enable the vulnerable DLL loading behavior
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Inspect current working directory for suspicious DLLsList all DLL files in the directory where curl will execute (ls *.dll on Windows or dir *.dll), specifically looking for security.dll, secur32.dll, or ws2_32.dllAffected if Any of the files security.dll, secur32.dll, or ws2_32.dll exist in the execution directory - these could be malicious DLLs injected by an attacker
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Check application directory for vulnerable DLLsList DLLs in the directory where curl.exe or the application using libcurl residesAffected if security.dll, secur32.dll, or ws2_32.dll are present in the application directory
A user is affected if they are running cURL/libcurl version 7.49.0 or earlier on Windows with SSPI or telnet support enabled, and malicious DLLs exist in directories from which the application loads DLLs.
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 cURL/libcurl to version 7.49.1 or later which includes the security fix. If upgrade is not feasible, ensure the application directory and any directory added to the search path are not writable by untrusted users, or rebuild curl without telnet/SSPI support if those features are unnecessary.
Fix this in Curl
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-4802 — 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-2016-4802 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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- Version or environment caveats, and links to real fixes
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