CVE-2011-5243
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 · uneditedTwitterOAuth does not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.
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 confidenceTwitterOAuth does not verify that the server hostname matches the Common Name (CN) or subjectAltName field of the X.509 certificate, allowing man-in-the-middle attackers to spoof SSL servers using any valid certificate.
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 dataall versionsCVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- None
AV:N/AC:M/Au:N/C:P/I:P/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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Locate TwitterOAuth library in the codebaseSearch for files containing 'twitteroauth' in the filename or class definitions (e.g., 'class TwitterOAuth'), or look for the 'twitteroauth' directory in vendor folders, include paths, or PHP project structureAffected if TwitterOAuth library is present in the project
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Find the HTTP request code that makes API callsSearch the TwitterOAuth source for calls to curl_setopt, curl_exec, or the HTTP client wrapper used to make requests to Twitter's API endpointsAffected if The library uses cURL or similar HTTP client without explicit SSL hostname verification
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Check SSL verification configuration for cURL callsInspect all curl_setopt calls before API requests, specifically looking for CURLOPT_SSL_VERIFYHOST and CURLOPT_SSL_VERIFYPEER settings. Verify whether CURLOPT_SSL_VERIFYHOST is set to 0 or 1 (should be 2 for proper verification) and CURLOPT_SSL_VERIFYPEER is not explicitly set to falseAffected if CURLOPT_SSL_VERIFYHOST is set to 0 or 1, or CURLOPT_SSL_VERIFYPEER is set to false, or these options are absent (defaulting to insecure behavior)
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Check if custom CA bundle is configuredLook for CURLOPT_CAINFO or CURLOPT_CAPATH settings that point to a valid CA certificate bundle file, or any custom SSL context configurationAffected if No custom CA bundle is configured and the library relies on system defaults without explicit verification
If TwitterOAuth is in use and SSL hostname verification (CURLOPT_SSL_VERIFYHOST set to 2) or peer verification (CURLOPT_SSL_VERIFYHOST) is disabled, missing, or improperly configured, the environment is vulnerable to MITM attacks.
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 dataUpdate TwitterOAuth to a version that implements proper SSL certificate hostname validation, or manually add certificate verification by configuring the cURL verification settings with valid CA certificates.
- Consultation2.0 h
- Implementation4.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-5243 — 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-2011-5243 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data