What is CVE-2020-9923?

CVE-2020-9923 is a high-severity vulnerability in Apple iOS, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2020-10-16.

How severe is CVE-2020-9923?

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

Buffer overflow in Apple iOS

CVE-2020-9923

A memory corruption issue was addressed with improved memory handling. This issue is fixed in iOS 13.6 and iPadOS 13.6, watchOS 6.2.8. A malicious application may be able to execute arbitrary code with system privileges.

Vulnerability class: Buffer Overflow

Published 2020-10-16 · 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: 0.012 (67.8th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 68th percentile — 67.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Apple iOS — versions unspecified
Apple Ipados
Apple Iphone OS
Apple watchOS — versions unspecified

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

support.apple.com/HT211288 (Release Notes, Vendor Advisory)
support.apple.com/HT211291 (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2020-9923?: CVE-2020-9923 is a high-severity vulnerability in Apple iOS, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2020-10-16.
How severe is CVE-2020-9923?: High severity. CVSS v3 base score is 7.8 out of 10.