iOS and iPadOS: Use After Free
CVE-2023-41976 is a high-severity use after free vulnerability in iOS and iPadOS from Apple, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 16.7, 17.1 as the first without the flaw, so updating iOS and iPadOS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.69% chance of exploitation within 30 days, higher than 77% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update iOS and iPadOS to 16.7 or 17.1, whichever matches your release line, or a later version.
- Update Safari to 17.1 or a later version.
- Update tvOS to 17.1 or a later version.
- Read the advisory on support.apple.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apple | iOS and iPadOS | before 16.7; before 17.1 | 16.7, 17.1 |
| Apple | Safari | before 17.1 | 17.1 |
| Apple | tvOS | before 17.1 | 17.1 |
| Apple | macOS | before 14.1 | 14.1 |
| Apple | watchOS | before 10.1 | 10.1 |
| Apple | iPadOS | before 16.7.2; 17.0 up to, but not including, 17.1 | 16.7.2, 17.1 |
| Apple | Iphone OS | before 16.7.2; 17.0 up to, but not including, 17.1 | 16.7.2, 17.1 |
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
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- 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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
A use-after-free issue was addressed with improved memory management. This issue is fixed in iOS 17.1 and iPadOS 17.1, watchOS 10.1, iOS 16.7.2 and iPadOS 16.7.2, macOS Sonoma 14.1, Safari 17.1, tvOS 17.1. Processing web content may lead to arbitrary code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- support.apple.com/en-us/HT213981Release Notes
- support.apple.com/en-us/HT213982Release Notes
- support.apple.com/en-us/HT213984Release Notes
- support.apple.com/en-us/HT213986Release Notes
- support.apple.com/en-us/HT213987Release Notes
- support.apple.com/en-us/HT213988Release Notes
Third-party and government advisories
- seclists.org/fulldisclosure/2023/Oct/19Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2023/Oct/22Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2023/Oct/23Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2023/Oct/24Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2023/Oct/25Mailing List, Third Party Advisory
- seclists.org/fulldisclosure/2023/Oct/27Mailing List, Third Party Advisory
Other references
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 Use After Free vulnerabilities
- 7.0 High severity
- 7.8 High severity
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
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