What is CVE-2021-1809?

CVE-2021-1809 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2021-09-08.

How severe is CVE-2021-1809?

High severity. CVSS v3 base score is 7.5 out of 10.

Buffer overflow in Apple iOS And Ipados

CVE-2021-1809

A memory corruption issue was addressed with improved validation. This issue is fixed in Security Update 2021-002 Catalina, Security Update 2021-003 Mojave, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5, macOS Big Sur 11.3. A malicious application may be able to read restricted memory.

Vulnerability class: Buffer Overflow

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

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.018 (77.3th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 77th percentile — 77.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.018 · newest: 0.018 · change: 0.000

Affected products

Apple iOS And Ipados — versions unspecified
Apple Ipados
Apple Iphone OS
Apple macOS — versions unspecified
Apple Mac OS X — versions 10.14.6, 10.15.6, 10.15.7
Apple tvOS — versions unspecified
Apple watchOS — versions unspecified

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

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)
support.apple.com/en-us/HT212326 (Vendor Advisory)
support.apple.com/en-us/HT212327 (Vendor Advisory)

Frequently asked questions

What is CVE-2021-1809?: CVE-2021-1809 is a high-severity vulnerability in Apple iOS And Ipados, classified under Out-of-bounds Write. CVSS score: 7.5/10. Published 2021-09-08.
How severe is CVE-2021-1809?: High severity. CVSS v3 base score is 7.5 out of 10.