What is CVE-2021-30883?

CVE-2021-30883 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2021-08-24.

How severe is CVE-2021-30883?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2021-30883 known to be exploited?

Yes. CVE-2021-30883 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 9 public proof-of-concept repositories are indexed.

Buffer overflow in Apple iOS And Ipados

CVE-2021-30883

A memory corruption issue was addressed with improved memory handling. This issue is fixed in iOS 15.0.2 and iPadOS 15.0.2, macOS Monterey 12.0.1, iOS 14.8.1 and iPadOS 14.8.1, tvOS 15.1, watchOS 8.1, macOS Big Sur 11.6.1. An application may be able to execute arbitrary code with kernel privileges. Apple is aware of a report that this issue may have been actively exploited..

Vulnerability class: Buffer Overflow

Published 2021-08-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.147 (96.6th percentile), scored 2026-10-18.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.147 · newest: 0.147 · change: 0.000

Affected products

Apple iOS And Ipados — versions unspecified
Apple Ipados
Apple Iphone OS
Apple macOS — versions unspecified, 12.0
Apple tvOS
Apple watchOS

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-05-23. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-06-13.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

support.apple.com/en-us/HT212869 (Vendor Advisory)
support.apple.com/en-us/HT212872 (Vendor Advisory)
support.apple.com/en-us/HT212846 (Vendor Advisory)
support.apple.com/en-us/HT212868 (Vendor Advisory)
support.apple.com/en-us/HT212874 (Vendor Advisory)
support.apple.com/en-us/HT212876 (Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2021-30883?: CVE-2021-30883 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2021-08-24.
How severe is CVE-2021-30883?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2021-30883 known to be exploited?: Yes. CVE-2021-30883 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-05-23), indicating it is being actively exploited. 9 public proof-of-concept repositories are indexed.