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IpadosOperating system · Apple

CVE-2021-30737

HIGH · 8.8 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.5 / 11.4 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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 · unedited
A memory corruption issue in the ASN.1 decoder was addressed by removing the vulnerable code. This issue is fixed in tvOS 14.6, Security Update 2021-004 Mojave, iOS 14.6 and iPadOS 14.6, iOS 12.5.4, Security Update 2021-003 Catalina, macOS Big Sur 11.4, watchOS 7.5. Processing a maliciously crafted certificate may lead to arbitrary code execution.

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 confidence

Memory corruption vulnerability in Apple's ASN.1 certificate decoder that can be triggered by processing a maliciously crafted certificate, potentially leading to arbitrary code execution. The vulnerability was addressed by removing the vulnerable decoder code.

MitigationApply the available security updates for affected Apple platforms: iOS 14.6/12.5.4, iPadOS 14.6, tvOS 14.6, watchOS 7.5, macOS Big Sur 11.4, and Security Updates 2021-003/004 for Catalina and Mojave.

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
IpadosOperating system
Affected:< 14.6
Iphone OsOperating system
Affected:< 12.5.4>= 13.0, < 14.6
Mac Os XOperating system
Affected:>= 10.14.0, <= 10.14.5>= 10.15, <= 10.15.5= 10.14.6= 10.15.6= 10.15.7
macOSOperating system
Affected:>= 11.0.1, < 11.4
TvosOperating system
Affected:< 14.6
WatchosOperating system
Affected:< 7.5

CVSS 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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device type and operating system version
    On iOS/iPadOS: Settings > General > About > Version. On macOS: Apple menu > About This Mac. On tvOS/watchOS: Settings > General > About > Version.
    Affected if The OS version falls outside the fixed releases (iOS/iPadOS 14.6+, iOS 12.5.4+, macOS 11.4+, tvOS 14.6+, watchOS 7.5+, or Security Updates 2021-003/004 for macOS 10.14/10.15)
  2. Confirm the specific macOS version if applicable
    Run 'sw_vers -productVersion' in Terminal, or check About This Mac for the exact version number.
    Affected if Running macOS Catalina (10.15.x) or Mojave (10.14.x) without Security Updates 2021-003 or 2021-004 applied, or running macOS Big Sur 11.0.1 through 11.3.x
  3. Understand the attack vector
    The vulnerability resides in the ASN.1 certificate decoder component of the operating system. It is triggered automatically when processing X.509 certificates from untrusted sources such as malicious websites, email attachments, or network endpoints.
    Affected if The device processes any certificate from an untrusted or attacker-controlled source while running a vulnerable OS version

A device is affected if it runs any iOS, iPadOS, tvOS, watchOS, or macOS version prior to the fixed releases (iOS 14.6/12.5.4, iPadOS 14.6, tvOS 14.6, watchOS 7.5, macOS 11.4, or macOS Security Updates 2021-003/004 for older macOS versions).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 7.5 / 11.4 / 12.5.4 or later
Fixed in 7.511.412.5.4
Interim mitigation

Apply the available security updates for affected Apple platforms: iOS 14.6/12.5.4, iPadOS 14.6, tvOS 14.6, watchOS 7.5, macOS Big Sur 11.4, and Security Updates 2021-003/004 for Catalina and Mojave.

Recommended fix High confidence

iOS 14.6 / iPadOS 14.6 / iOS 12.5.4 / macOS Big Sur 11.4 / Security Update 2021-004 Mojave / Security Update 2021-003 Catalina / tvOS 14.6 / watchOS 7.5

  1. Identify the Apple device type (iPhone, iPad, Mac, Apple TV, or Apple Watch)
  2. Determine the current installed OS version from Settings > General > About (iOS/iPadOS/tvOS/watchOS) or System Preferences > About (macOS)
  3. For iPhone/iPad: Upgrade to iOS 14.6 or iPadOS 14.6 (or iOS 12.5.4 for devices on iOS 12)
  4. For Mac: Upgrade to macOS Big Sur 11.4 or apply Security Update 2021-004 (Mojave) / Security Update 2021-003 (Catalina)
  5. For Apple TV: Upgrade to tvOS 14.6
  6. For Apple Watch: Upgrade to watchOS 7.5
  7. Verify the upgrade was successful by checking the OS version again
Caveat Major OS upgrades (e.g., from iOS 12 to 14, or macOS 10.x to 11) may introduce UI changes, remove support for older apps, or have compatibility issues with legacy software

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ipados Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-30737 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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