CVE-2019-5431
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 · uneditedThis vulnerability was caused by an incomplete fix to CVE-2017-0911. Twitter Kit for iOS versions 3.0 to 3.4.0 is vulnerable to a callback verification flaw in the "Login with Twitter" component allowing an attacker to provide alternate credentials. In the final step of "Login with Twitter" authentication information is passed back to the application using the registered custom URL scheme (typically twitterkit-<consumer-key>) on iOS. Because the callback handler did not verify the authenticity of the response, this step is vulnerable to forgery, potentially allowing attacker to associate a Twitter account with a third-party service.
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 confidenceThis is a callback verification flaw in Twitter Kit for iOS versions 3.0-3.4.0. The OAuth callback handler fails to verify the authenticity of the response sent via the custom URL scheme (twitterkit-<consumer-key>), allowing attackers to forge authentication callbacks and potentially associate a victim's Twitter account with a third-party service. This was an incomplete fix to CVE-2017-0911.
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>= 3.0, <= 3.4.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/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 if Twitter Kit for iOS is presentSearch your project files for Twitter Kit references: check Podfile/Podfile.lock for 'TwitterKit' pod, or examine the linked frameworks in your Xcode project for TwitterKit.frameworkAffected if Twitter Kit for iOS is found in the project dependencies
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Determine the installed Twitter Kit versionIf using CocoaPods, read the version from Podfile.lock under the TwitterKit entry. If using manual linking, right-click TwitterKit.framework in Xcode and select 'Get Info' to view the version, or check the release notes bundled with the frameworkAffected if The version listed is 3.0, 3.1.x, 3.2.x, 3.3.x, or 3.4.0
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Confirm OAuth callback handling is in useSearch your app's source code for implementations of UIApplicationDelegate methods handling custom URL schemes, particularly looking for 'twitterkit-' prefix in URL handling logic or usage of TWTRComposer or TWTRSession in authentication flowsAffected if The application uses Twitter OAuth authentication via Twitter Kit with custom URL scheme callbacks (twitterkit-<consumer-key>)
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Verify the callback URL scheme configurationExamine your app's Info.plist file under CFBundleURLTypes for any registered URL schemes starting with 'twitterkit-'Affected if A custom URL scheme matching 'twitterkit-' pattern is registered for OAuth callbacks
Your environment is affected if Twitter Kit for iOS version 3.0 through 3.4.0 is installed and your application uses Twitter OAuth authentication with the vulnerable custom URL scheme callback handler.
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 Twitter Kit for iOS to version 3.4.1 or later which contains the complete fix. If upgrade is not feasible, implement additional server-side validation of OAuth tokens before trusting the authentication response.
- Consultation3.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-5431 — 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-2019-5431 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