CVE-2020-9920
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 path handling issue was addressed with improved validation. This issue is fixed in iOS 13.6 and iPadOS 13.6, macOS Catalina 10.15.6, watchOS 6.2.8. A malicious mail server may overwrite arbitrary mail files.
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 confidenceA path traversal vulnerability in Apple's Mail app allowed a malicious mail server to write files to arbitrary filesystem locations by using path traversal sequences (e.g., '../') in file attachments or mail storage operations, potentially overwriting system files or user data.
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< 13.6< 13.6< 10.15.6< 6.2.8CVSS 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
- None
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 iOS version on iPhoneOpen Settings > General > About and note the version number displayed next to 'Version'Affected if The version is lower than 13.6 (for example, 13.5 or earlier)
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Check iPadOS version on iPadOpen Settings > General > About and note the version number displayed next to 'Version'Affected if The version is lower than 13.6
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Check macOS versionClick the Apple menu > About This Mac and note the version number (for example, 10.15.5)Affected if The version is lower than 10.15.6
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Check watchOS versionOpen the Watch app on your paired iPhone, go to General > About and note the versionAffected if The version is lower than 6.2.8
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Determine if Apple Mail app is in useLocate the Mail app icon (envelope with blue background) on your device home screen or in the app libraryAffected if The Mail app is installed and used to fetch or view email messages
You are affected if your device runs an OS version lower than the patched release (iOS 13.6, iPadOS 13.6, macOS 10.15.6, or watchOS 6.2.8) and you use the Apple Mail application.
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 · scoped6.2.810.15.613.6
Apply vendor patches by updating to iOS 13.6/iPadOS 13.6, macOS Catalina 10.15.6, watchOS 6.2.8 or later. Until patched, restrict mail server connections to trusted sources and disable automatic mail fetching.
iOS 13.6, iPadOS 13.6, macOS 10.15.6, or watchOS 6.2.8 (or later)
- Back up your device data before performing any system update
- For iOS/iPadOS devices: Go to Settings > General > Software Update and install iOS 13.6 or later / iPadOS 13.6 or later
- For macOS devices: Open System Preferences > Software Update and install macOS Catalina 10.15.6 or later
- For Apple Watch: Open the Watch app on your paired iPhone, go to General > Software Update, and install watchOS 6.2.8 or later
- After updating, verify the update was successful by checking the OS version in Settings/General/About
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
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-9920 — 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-2020-9920 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