What is CVE-2021-1864?

CVE-2021-1864 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Use After Free. CVSS score: 9.8/10. Published 2021-09-08.

How severe is CVE-2021-1864?

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

Use After Free in Apple iOS And Ipados

CVE-2021-1864

A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. An attacker with JavaScript execution may be able to execute arbitrary code.

Vulnerability class: Use-After-Free

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: 0.022 (81.5th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 82nd percentile — 81.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.022 · newest: 0.022 · change: 0.000

Affected products

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

Weakness classification (CWE)

CWE-416 — Use After Free

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)

Frequently asked questions

What is CVE-2021-1864?: CVE-2021-1864 is a critical-severity vulnerability in Apple iOS And Ipados, classified under Use After Free. CVSS score: 9.8/10. Published 2021-09-08.
How severe is CVE-2021-1864?: Critical severity. CVSS v3 base score is 9.8 out of 10.