Is CVE-2021-30663 actively exploited?

Yes. KEV Intelligence tracks CVE-2021-30663 as a known exploited vulnerability. Confidence is confirmed.

What exploitation activity has KEV Intelligence observed?

KEV Intelligence has not yet recorded sensor-observed exploitation attempts for CVE-2021-30663. Our sensors continue to monitor for activity targeting this CVE.

Which versions are affected?

CVE-2021-30663 affects Apple macOS. KEV Intelligence lists 5 version rows; examples include unspecified to < 11.3, unspecified to < 14.5, and unspecified to < 12.5.

Yes. CVE-2021-30663 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-30663

Q: How should organizations remediate it?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Q: Is it in CISA KEV?

Yes. CVE-2021-30663 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

macOS

Apple / macOS · affected before 11.3

View live feed Monitor via API

Severity: CVSS 8.8 · High
Confidence: Confirmed
Exploit status: Exploited in the wild
EPSS: 3.5%
First observed: —
Last observed: —

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-30663 is an unauthenticated vulnerability affecting Apple macOS. An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3,...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

Apple / macOS affected before 11.3.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

An integer overflow was addressed with improved input validation

An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1.

Processing maliciously crafted web content may lead to arbitrary code execution.

Vendor Product Affected Status

Apple macOS Before 11.3 Affected

Apple macOS Before 14.5 Affected

Apple macOS Before 12.5 Affected

Apple macOS Before 14.6 Affected

Apple macOS Before 14.1 Affected

Published: 08 Sep 2021
Exploitation Reported: 03 Nov 2021
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: Required

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2021-30663
support.apple.com/en-us/HT212532 support.apple.com · CVE Record https://support.apple.com/en-us/HT212532
support.apple.com/en-us/HT212534 support.apple.com · CVE Record https://support.apple.com/en-us/HT212534
support.apple.com/en-us/HT212341 support.apple.com · CVE Record https://support.apple.com/en-us/HT212341
support.apple.com/en-us/HT212335 support.apple.com · CVE Record https://support.apple.com/en-us/HT212335
support.apple.com/en-us/HT212336 support.apple.com · CVE Record https://support.apple.com/en-us/HT212336

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 03 Nov 2021

Independent exploitation attestation added to the KEV Intelligence record.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source	Added
CISA First	2021-11-03 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets: 0
User-Agents: 0

Raw values available in Pro and Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

8.8 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS

3.5%

Weaknesses

Integer Overflow or Wraparound CWE-190

All CVSS Scores

CVSS v3.1 8.8 High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v2.0 6.8 Medium

AV:N/AC:M/Au:N/C:P/I:P/A:P

Timeline

From disclosure to observed exploitation

03 Nov 2021
Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
08 Sep 2021
CVE published

Vulnerability disclosed publicly
13 Apr 2021
CVE ID reserved

Identifier reserved by the CNA

Pro API

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Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-30663

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2021-30663",
  "confidence": "Confirmed",
  "cvss_score": 8.8,
  "cvss_estimated": false,
  "epss_score": 0.03493,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

Early warning alerts

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