What is CVE-2021-30665?

CVE-2021-30665 is a high-severity vulnerability in Apple Ipados, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-09-08.

How severe is CVE-2021-30665?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2021-30665 known to be exploited?

Yes. CVE-2021-30665 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.

Buffer overflow in Apple Ipados

CVE-2021-30665

A memory corruption issue was addressed with improved state management. This issue is fixed in watchOS 7.4.1, iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

Vulnerability class: Buffer Overflow

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

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.037 (89.6th percentile), scored 2026-10-19.

Low probability of exploitation in the next 30 days, but still tracked. 90th percentile — 89.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.037 · newest: 0.037 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

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: 2021-11-17.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

support.apple.com/en-us/HT212532 (Release Notes, Vendor Advisory)
support.apple.com/en-us/HT212341 (Release Notes, Vendor Advisory)
support.apple.com/en-us/HT212335 (Release Notes, Vendor Advisory)
support.apple.com/en-us/HT212336 (Release Notes, Vendor Advisory)
support.apple.com/en-us/HT212339 (Release Notes, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory, US Government Resource)

Frequently asked questions

What is CVE-2021-30665?: CVE-2021-30665 is a high-severity vulnerability in Apple Ipados, classified under Out-of-bounds Write. CVSS score: 8.8/10. Published 2021-09-08.
How severe is CVE-2021-30665?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2021-30665 known to be exploited?: Yes. CVE-2021-30665 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.