What is CVE-2021-1770?

CVE-2021-1770 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2021-09-08.

How severe is CVE-2021-1770?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Apple iOS And Ipados

CVE-2021-1770

A buffer overflow may result in arbitrary code execution. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. A logic issue was addressed with improved state management.

Vulnerability class: Buffer Overflow

Published 2021-09-08 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.028 (85.7th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.028 · newest: 0.028 · change: 0.000

Affected products

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

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

support.apple.com/en-us/HT212317 (Vendor Advisory)
support.apple.com/en-us/HT212323 (Vendor Advisory)
support.apple.com/en-us/HT212324 (Vendor Advisory)
support.apple.com/en-us/HT212325 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-1770?: CVE-2021-1770 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2021-09-08.
How severe is CVE-2021-1770?: Critical severity. CVSS v3 base score is 9.8 out of 10.