CVE-2021-1837
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 certificate validation issue was addressed. This issue is fixed in iOS 14.5 and iPadOS 14.5. An attacker in a privileged network position may be able to alter network traffic.
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 confidenceCertificate validation bypass in iOS/iPadOS allows a privileged network attacker to perform a man-in-the-middle attack and alter network traffic. The vulnerability stems from improper certificate chain validation, enabling spoofed TLS connections.
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< 14.5< 14.5CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:H/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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Check iOS version on iPhoneGo to Settings > General > About on the iPhone and look at the 'Version' fieldAffected if Version shows a number lower than 14.5 (for example, 14.4.2, 14.3, 13.x)
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Check iPadOS version on iPadGo to Settings > General > About on the iPad and look at the 'Version' fieldAffected if Version shows a number lower than 14.5 (for example, 14.4.1, 14.2, 13.x)
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Confirm device model matches iOS scopeVerify the device is an iPhone by checking the model name in Settings > General > About under 'Model Name'Affected if Device is an iPhone running any iOS version below 14.5
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Confirm device model matches iPadOS scopeVerify the device is an iPad by checking the model name in Settings > General > About under 'Model Name'Affected if Device is an iPad running any iPadOS version below 14.5
The device is affected if it is an iPhone or iPad running iOS/iPadOS version 14.4 or lower.
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 · scoped14.5
Update affected iOS devices to version 14.5 or later, and iPadOS devices to 14.5 or later. For enterprise deployments, use Mobile Device Management (MDM) to verify and enforce the OS update across all managed devices.
iOS 14.5 and iPadOS 14.5
- Back up your iPhone or iPad data using iCloud or your computer before updating
- Connect your device to power and ensure it has sufficient battery or is plugged in
- Connect your device to Wi-Fi
- Go to Settings > General > Software Update on your device
- Download and install iOS 14.5 or later (for iPhone) or iPadOS 14.5 or later (for iPad)
- Restart your device after the update completes
Generated from the published advisory — verify against the referenced sources before acting.
- 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-2021-1837 — 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-2021-1837 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