Background exploitation KEV catalog
CVE-2021-30900

Apple iOS, iPadOS, and macOS Out-of-Bounds Write Vulnerability

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 14.8.1 and iPadOS 14.8.1, iOS 15.1 and iPadOS 15.1. A malicious application may be able to execute arbitrary code with kernel privileges.

CheckOps priority index
4.5/10 Patch within 7 days
Severity7.8
Probability0.5
Exploitation2/5

Severity = CVSS. Probability = EPSS (FIRST). Exploitation = public signals: KEV, EUVD, ransomware, EPSS above 10 %, no account required.

EPSS · today 5.2% higher than 92.5% of CVEs
CVSS 3.1 7.8 AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:
Exploited for 1,314 days 30 Mar 2023
CISA due date 20 Apr 2023 for US federal agencies

Exploitation probability EPSS · FIRST

05010026 Sep05 Oct15 Oct24 Oct02 Nov
EPSS probability (%)Percentile among all CVEs

Exploitation signals 2 / 5

  • KEV catalog (CISA)30 Mar 2023
  • Exploited in EUVD (ENISA)30 Mar 2023
  • Used by ransomwareno
  • EPSS above 10 %5.2%
  • No account, over the networkno

What to do

Fix

Apply the vendor’s fix as soon as it is available.

CISA guidance: Apply updates per vendor instructions.

Meanwhile

Take the service off the internet or restrict access to it, watch the logs and look for signs of compromise.

Manufacturers (CRA)

Exploited vulnerability in your product: early warning to ENISA within 24 h, then notification within 72 h (Article 14 of the Cyber Resilience Act). The CRA explained

Affected products

iOS and iPadOSiOS, iPadOS, and macOS
Affected versions
  • unspecified <14.8
  • unspecified <15.1
Weaknesses (CWE)

Open source packages OSV

Affected libraries according to OSV, with fixed versions.

Timeline

  1. Published

  2. Exploitation reported (ENISA)

  3. Added to the KEV catalog

  4. CISA remediation due date

References

Other exploited vulnerabilities from the same vendor

  • CVE-2026-86950Apple Multiple Products Out-of-Bounds Write Vulnerability
    6.7 · Actively exploited
  • CVE-2026-65400Apple macOS Improper Authentication Vulnerability
    5.8 · Actively exploited
  • CVE-2025-43520Apple Multiple Products Classic Buffer Overflow Vulnerability
    3.4 · Background exploitation
  • CVE-2025-43510Apple Multiple Products Improper Locking Vulnerability
    4.3 · Background exploitation
  • CVE-2025-31277Apple Multiple Products Buffer Overflow Vulnerability
    5.4 · Background exploitation
  • CVE-2023-43000Apple Multiple products Use-After-Free Vulnerability
    5.4 · Background exploitation

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Sources: CISA KEV · ENISA EUVD · FIRST EPSS · OSV. Public data aggregated by CheckOps, updated automatically. Source texts remain the property of their authors. All exploited vulnerabilities