CVE-2021-1766 Denial of service in iOS and iPadOS
Attackers can cause a denial of service by tricking users into opening a maliciously crafted image on Apple devices.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2021-1766?
CVE-2021-1766 is a medium-severity denial of service vulnerability in Apple Ipados, published on 2 Apr 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
This issue was addressed with improved checks. 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. Processing a maliciously crafted image may lead to a denial of service.
Which versions are affected by CVE-2021-1766?
It affects 6 products.
Products include Apple Ipados, Apple Iphone Os, Apple Mac Os X, Apple Macos, Apple Tvos, Apple Watchos.
How do I fix CVE-2021-1766?
No fix has been published for CVE-2021-1766 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2021-1766 being exploited?
There is no known exploitation of CVE-2021-1766 in the wild and no public exploit code.
Other vulnerabilities in Apple Ipados
- CVE-2025-43300 Apple iOS, iPadOS, and macOS Out-of-Bounds Write
- CVE-2025-24201 Apple Multiple Products WebKit Out-of-Bounds Write
- CVE-2025-24085 Apple Multiple Products Use-After-Free
- CVE-2025-31200 Apple Multiple Products Memory Corruption
- CVE-2025-31201 Apple Multiple Products Arbitrary Read and Write
Sources
Also known as GHSA-rr24-55gg-g58c.