What is CVE-2021-30736?

CVE-2021-30736 is a high-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.8/10. Published 2021-09-08.

How severe is CVE-2021-30736?

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

Buffer overflow in Apple iOS And Ipados

CVE-2021-30736

A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Big Sur 11.4, tvOS 14.6, watchOS 7.5, iOS 14.6 and iPadOS 14.6. An application may be able to execute arbitrary code with kernel privileges.

Vulnerability class: Buffer Overflow

Published 2021-09-08 · 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: 0.016 (75.2th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 75.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

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

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

support.apple.com/en-us/HT212528 (Vendor Advisory)
support.apple.com/en-us/HT212529 (Vendor Advisory)
support.apple.com/en-us/HT212532 (Vendor Advisory)
support.apple.com/en-us/HT212533 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-30736?: CVE-2021-30736 is a high-severity vulnerability in Apple iOS And Ipados, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 7.8/10. Published 2021-09-08.
How severe is CVE-2021-30736?: High severity. CVSS v3 base score is 7.8 out of 10.