dbcve.org
IpadosOperating system · Apple

CVE-2021-1883

MEDIUM · 5.5 CVSS v3.1 Published 2021-09-08
Fix available
A fix is available. Upgrade to 7.4 / 11.3 or later.
See remediation →
58/100
Remediation priority · Elevated
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
This issue was addressed with improved checks. This issue is fixed in Security Update 2021-004 Mojave, iOS 14.5 and iPadOS 14.5, watchOS 7.4, Security Update 2021-003 Catalina, tvOS 14.5, macOS Big Sur 11.3. Processing maliciously crafted server messages may lead to heap corruption.

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 confidence

A heap corruption vulnerability exists in multiple Apple operating systems (iOS, iPadOS, watchOS, macOS, tvOS) that allows heap corruption when processing maliciously crafted server messages. The vulnerability stems from insufficient validation checks during message parsing, allowing an attacker to overwrite heap memory via specially crafted network responses.

MitigationApply the appropriate security update for each affected Apple product: iOS 14.5, iPadOS 14.5, watchOS 7.4, macOS Big Sur 11.3/Security Update 2021-003/2021-004, or tvOS 14.5. This vulnerability is addressed with improved input validation checks.

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:< 14.5
Iphone OsOperating system
Affected:< 14.5
Mac Os XOperating system
Affected:>= 10.14, <= 10.14.5>= 10.15, <= 10.15.5= 10.14.6= 10.15.6= 10.15.7
macOSOperating system
Affected:>= 11.0, < 11.3
TvosOperating system
Affected:< 14.5
WatchosOperating system
Affected:< 7.4

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
Local
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

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

  1. Identify the Apple device type
    Determine whether the system is running iOS, iPadOS, watchOS, macOS, or tvOS. On macOS, run 'sw_vers' or check System Preferences > About. On iOS/iPadOS, go to Settings > General > About. On watchOS, use the Watch app on iPhone or check Settings > General > About on the watch.
    Affected if Device runs any of the affected Apple operating systems
  2. Check the installed iOS version
    On iOS device, go to Settings > General > About and note the Version number. Alternatively, connect to a computer with iTunes or Finder and check the device information.
    Affected if iOS version is lower than 14.5
  3. Check the installed iPadOS version
    On iPadOS device, go to Settings > General > About and note the Version number.
    Affected if iPadOS version is lower than 14.5
  4. Check the installed macOS version
    Run 'sw_vers' in Terminal to get the version number and build. Or go to Apple menu > About This Mac > Version.
    Affected if macOS version is 10.14.x through 10.14.6, 10.15.x through 10.15.7, or 11.0 through 11.2.x (any version >= 11.0 but < 11.3)
  5. Check the installed tvOS version
    Go to Settings > General > About > Version on Apple TV, or check via Home Sharing computer.
    Affected if tvOS version is lower than 14.5
  6. Check the installed watchOS version
    On Apple Watch, go to Settings > General > About and note the Version. Or open Watch app on paired iPhone, go to My Watch > General > About.
    Affected if watchOS version is lower than 7.4

The system is affected if it runs any Apple OS version that falls within the listed affected ranges: iOS/iPadOS/tvOS/watchOS below 14.5/7.4, or macOS versions 10.14.x-10.14.6, 10.15.x-10.15.7, or 11.0-11.2.x.

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 7.4 / 11.3 / 14.5 or later
Fixed in 7.411.314.5
Interim mitigation

Apply the appropriate security update for each affected Apple product: iOS 14.5, iPadOS 14.5, watchOS 7.4, macOS Big Sur 11.3/Security Update 2021-003/2021-004, or tvOS 14.5. This vulnerability is addressed with improved input validation checks.

Recommended fix High confidence

iOS 14.5 / iPadOS 14.5 / watchOS 7.4 / tvOS 14.5 / macOS Big Sur 11.3 / Security Update 2021-003 Catalina / Security Update 2021-004 Mojave

  1. Check current device OS version in Settings > General > About (iOS/iPadOS) or System Preferences > General > Software Update (macOS)
  2. For iPhone/iPad: Upgrade to iOS 14.5 or later via Settings > General > Software Update
  3. For Apple Watch: Upgrade to watchOS 7.4 or later via the Watch app on iPhone
  4. For Apple TV: Upgrade to tvOS 14.5 or later via Settings > System > Software Update
  5. For macOS Big Sur (11.x): Upgrade to macOS 11.3 or later via System Preferences > Software Update
  6. For macOS Catalina (10.15): Install Security Update 2021-003 via System Preferences > Software Update
  7. For macOS Mojave (10.14): Install Security Update 2021-004 via System Preferences > Software Update
  8. Restart the device after applying the update
Caveat Standard OS update with no expected breaking changes; this is a security-only patch

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

Fix this in Ipados Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
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Scan for this in your stack

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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-2021-1883 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