What is CVE-2020-9859?

CVE-2020-9859 is a high-severity vulnerability in Apple iOS, classified under Double Free. CVSS score: 7.8/10. Published 2020-06-05.

How severe is CVE-2020-9859?

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

Is CVE-2020-9859 known to be exploited?

Yes. CVE-2020-9859 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.

Double Free in Apple iOS

CVE-2020-9859

A memory consumption issue was addressed with improved memory handling. This issue is fixed in iOS 13.5.1 and iPadOS 13.5.1, macOS Catalina 10.15.5 Supplemental Update, tvOS 13.4.6, watchOS 6.2.6. An application may be able to execute arbitrary code with kernel privileges.

Vulnerability class: Double Free

Published 2020-06-05 · last modified 2026-06-17.

CVSS v3 metric

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

EPSS exploit prediction

EPSS: 0.008 (56.7th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 56.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Apple iOS — versions unspecified
Apple Ipados
Apple Iphone OS
Apple macOS — versions unspecified
Apple Mac OS X
Apple tvOS — versions unspecified
Apple watchOS — versions unspecified

Weakness classification (CWE)

CWE-415 — Double Free

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. 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: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

support.apple.com/HT211214 (Release Notes, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2020-9859?: CVE-2020-9859 is a high-severity vulnerability in Apple iOS, classified under Double Free. CVSS score: 7.8/10. Published 2020-06-05.
How severe is CVE-2020-9859?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2020-9859 known to be exploited?: Yes. CVE-2020-9859 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.