Apple

CVE-2021-1801: This issue was addressed with improved iframe sandbox enforcement.

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of 29 Oct 2026.

VulnCheck KEV lists it since 27 Sep 2023. It cites 1 public report, the first from 27 Sep 2023.

confiant.com

How likely is exploitation in the next 30 days?

1.5%

EPSS score, percentile 74.5 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

Not scored

The CVE record carries no CVSS score.

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (3)

Which versions are affected?

Affected

before 14.4
before 11.2
before 7.3
before 14.4

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; VulnCheck KEV, as of 30 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 30 Oct 2026. About the data.

Description

This issue was addressed with improved iframe sandbox enforcement. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. Maliciously crafted web content may violate iframe sandboxing policy.

Source: CVE List, as of 30 Oct 2026. About the data.

What to do

Advisories and patches

FEDORA-2021-864dc37032 (Vendor advisory)
FEDORA-2021-619711d709 (Vendor advisory)
GLSA-202104-03 (Vendor advisory)

This summary is based on the CVE record as of 30 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (4 products)

Apple iOS and iPadOS
Status	Versions
Affected	before 14.4

Apple macOS
Status	Versions
Affected	before 11.2

Apple macOS
Status	Versions
Affected	before 7.3

Apple macOS
Status	Versions
Affected	before 14.4

Source: CVE List, as of 30 Oct 2026. About the data.

Timeline

Date	Event
2 Apr 2021	CVE record published
3 Aug 2024	CVE record last updated

References

Known exploited Apple vulnerabilities

CVE-2026-86950: Apple Multiple Products Out-of-Bounds Write Vulnerability (added 29 Sep 2026)
CVE-2026-65400: Apple macOS Improper Authentication Vulnerability (added 18 Aug 2026)
CVE-2025-31277: Apple Multiple Products Buffer Overflow Vulnerability (added 20 Mar 2026)
CVE-2025-43510: Apple Multiple Products Improper Locking Vulnerability (added 20 Mar 2026)
CVE-2025-43520: Apple Multiple Products Classic Buffer Overflow Vulnerability (added 20 Mar 2026)