Apple · Multiple Products
CVE-2021-1789
Apple Multiple Products Type Confusion Vulnerability
What it is
A type confusion issue was addressed with improved state handling. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, tvOS 14.4, watchOS 7.3, iOS 14.4 and iPadOS 14.4, Safari 14.0.3. Processing maliciously crafted web content may lead to arbitrary code execution.
CISA: A type confusion issue affecting multiple Apple products allows processing of maliciously crafted web content, leading to arbitrary code execution.
What to do
Apply updates per vendor instructions.
Deadline for US federal agencies: May 25, 2022
- Added to the CISA list
- May 4, 2022
- Published
- April 2, 2021
- Severity
- High 8.8 CVSS 3.1
- Chance of attacks in the next 30 days (EPSS)
- 14% in the top 3.5% of all known vulnerabilities
- Weakness
- CWE-843
- More details
- NVD · CVE.org · CISA
All references (8)
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/L3L6ZZOU5JS7…
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JN6ZOD62CTO5…
- https://security.gentoo.org/glsa/202104-03
- https://support.apple.com/en-us/HT212147
- https://support.apple.com/en-us/HT212146
- https://support.apple.com/en-us/HT212148
- https://support.apple.com/en-us/HT212149
- https://support.apple.com/en-us/HT212152
More exploited flaws from Apple
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 29, 2026 | Out-of-Bounds Write | Multiple Products | High 8.8 | 26% |
| Mar 20, 2026 | Buffer Overflow | Multiple Products | High 8.8 | 1.7% |
| Mar 20, 2026 | Improper Locking | Multiple Products | High 7.8 | 0.4% |
| Mar 20, 2026 | Classic Buffer Overflow | Multiple Products | Medium 5.5 | 0.4% |
| Mar 5, 2026 | Integer Overflow or Wraparound | Multiple Products | High 8.8 | 7.0% |
| Mar 5, 2026 | Use-After-Free | Multiple Products | High 8.8 | 4.0% |
| Feb 12, 2026 | Multiple Buffer Overflow | Multiple Products | High 7.8 | 1.7% |
| Dec 15, 2025 | Use-After-Free WebKit | Multiple Products | High 8.8 | 26% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.