Apple iOS, iPadOS, and macOS Webkit Use-After-Free
CVE-2022-22620 is a high-severity use after free vulnerability in Safari (v and ) 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 version 15.3 as the first without the flaw, so updating Safari (v and ) to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on February 11, 2022, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Safari (v and ) to 15.3 or a later version.
- Update macOS to 12.2 or 15.3, whichever matches your release line, or a later version.
- Update Safari to 15.3 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- 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 | Safari (v and ) | before 15.3 | 15.3 |
| Apple | macOS | before 12.2; before 15.3 | 12.2, 15.3 |
| Apple | Safari | before 15.3 | 15.3 |
| Apple | iPadOS | before 15.3.1 | 15.3.1 |
| Apple | Iphone OS | before 15.3.1 | 15.3.1 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 2.0 | 6.8 | Medium | NVD |
Official description
A use after free issue was addressed with improved memory management. This issue is fixed in macOS Monterey 12.2.1, iOS 15.3.1 and iPadOS 15.3.1, Safari 15.3 (v. 16612.4.9.1.8 and 15612.4.9.1.8). Processing maliciously crafted web content may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..
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
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CVE record published.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- support.apple.com/en-us/HT213091Release Notes
- support.apple.com/en-us/HT213092Release Notes
- support.apple.com/en-us/HT213093Release Notes
Third-party and government advisories
- security.gentoo.org/glsa/202208-39Third Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-22620Third Party Advisory, US Government Resource
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
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