Apple Multiple Buffer Overflow
CVE-2026-20700 is a high-severity improper restriction of operations within the bounds of a memory buffer vulnerability in iOS and iPadOS from Apple, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 26.3 as the first without the flaw, so updating iOS and iPadOS to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on February 12, 2026, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update iOS and iPadOS to 26.3 or a later version.
- Update macOS to 26.3 or a later version.
- Update tvOS to 26.3 or a later version.
- CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- Read the advisory on support.apple.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apple | iOS and iPadOS | before 26.3 | 26.3 |
| Apple | macOS | before 26.3 | 26.3 |
| Apple | tvOS | before 26.3 | 26.3 |
| Apple | visionOS | before 26.3 | 26.3 |
| Apple | watchOS | before 26.3 | 26.3 |
| Apple | iPadOS | before 26.3 | 26.3 |
| Apple | Iphone OS | before 26.3 | 26.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
A memory corruption issue was addressed with improved state management. This issue is fixed in iOS 26.3 and iPadOS 26.3, macOS Tahoe 26.3, tvOS 26.3, visionOS 26.3, watchOS 26.3. An attacker with memory write capability may be able to execute arbitrary code. Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals on versions of iOS before iOS 26. CVE-2025-14174 and CVE-2025-43529 were also issued in response to this report.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.
How developers prevent this class of flaw
- Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- support.apple.com/en-us/126346Release Notes
- support.apple.com/en-us/126348Release Notes
- support.apple.com/en-us/126351Release Notes
- support.apple.com/en-us/126352Release Notes
- support.apple.com/en-us/126353Release Notes
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20700US Government Resource
Other vulnerabilities in iOS and iPadOS
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.2 High severity
- 7.2 High severity
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