CVE-2022-42856
Apple iOS Type Confusion Vulnerability
Description
CVE-2022-42856 is a type confusion vulnerability in Apple's WebKit browser engine, affecting Safari, iOS, iPadOS, macOS Ventura, and tvOS. When a user visits a maliciously crafted webpage, the type confusion flaw can be triggered, potentially allowing an attacker to execute arbitrary code on the victim's device. Apple confirmed that CVE-2022-42856 was actively exploited in the wild against iOS versions released before iOS 15.1, prompting its inclusion in CISA's Known Exploited Vulnerabilities catalog with a remediation deadline of January 4, 2023. With a CVSS score of 8.8 (High) and a network-based attack vector requiring only user interaction, this vulnerability poses a significant risk to unpatched Apple devices.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| apple | safari | < 16.2 |
| apple | ipados | < 15.7.2 |
| apple | iphone os | < 15.7.2; >= 16.0, < 16.1.2 |
| apple | macos | < 13.1 |
| apple | tvos | < 16.2 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- http://seclists.org/fulldisclosure/2022/Dec/21(Mailing List, Third Party Advisory)
- http://seclists.org/fulldisclosure/2022/Dec/22(Mailing List, Third Party Advisory)
- http://seclists.org/fulldisclosure/2022/Dec/23(Mailing List, Third Party Advisory)
- http://seclists.org/fulldisclosure/2022/Dec/26(Mailing List, Third Party Advisory)
- http://seclists.org/fulldisclosure/2022/Dec/28(Mailing List, Third Party Advisory)
- http://www.openwall.com/lists/oss-security/2022/12/26/1(Mailing List, Third Party Advisory)
- https://security.gentoo.org/glsa/202305-32(Third Party Advisory)
- https://support.apple.com/en-us/HT213516(Release Notes, Vendor Advisory)
- https://support.apple.com/en-us/HT213531(Release Notes, Vendor Advisory)
- https://support.apple.com/en-us/HT213532(Release Notes, Vendor Advisory)
- https://support.apple.com/en-us/HT213535(Release Notes, Vendor Advisory)
- https://support.apple.com/en-us/HT213537(Release Notes, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-42856(US Government Resource)
Weakness Type
CWE-843: Access of Resource Using Incompatible Type (Type Confusion)
Type confusion vulnerabilities occur when a program accesses a resource using a type that is incompatible with its actual type. In the case of CVE-2022-42856, WebKit's processing of web content could misinterpret the type of an object in memory, leading to unexpected behavior and ultimately enabling arbitrary code execution. This class of vulnerability is particularly dangerous in browser engines because it can be triggered simply by visiting a webpage.
Learn more: CWE-843 — Access of Resource Using Incompatible Type
Impact Analysis
Confidentiality Impact: High — successful exploitation of CVE-2022-42856 can grant an attacker full read access to sensitive data stored on the affected device, including credentials, personal files, and browser session data. Integrity Impact: High — the type confusion flaw allows arbitrary code execution, meaning attackers can modify system files, install malware, or alter application behavior without the user's knowledge. Availability Impact: High — exploitation can lead to device instability, application crashes, or a complete denial of service. Scope: The vulnerability is contained within the affected application context (Scope Unchanged), though code execution at the application level on mobile devices can still yield significant control. Attack Prerequisites: The attack requires network access and user interaction — specifically, the victim must navigate to a malicious or compromised website. No authentication or special privileges are needed by the attacker, making CVE-2022-42856 broadly exploitable against any user running a vulnerable version of Safari, iOS, iPadOS, macOS Ventura, or tvOS.
Exploit Maturity
Active Exploitation: Apple acknowledged that CVE-2022-42856 may have been actively exploited in the wild against iOS versions released before iOS 15.1, confirming real-world abuse of this vulnerability. KEV Catalog Status: CISA added this vulnerability to its Known Exploited Vulnerabilities catalog, mandating federal agencies to remediate by January 4, 2023. EPSS Score: The EPSS score is 0.00187 (40th percentile), indicating a relatively low predicted probability of widespread future exploitation, likely because Apple quickly released patches and the exploit targeted older iOS versions. Ransomware Association: There is no confirmed association between CVE-2022-42856 and ransomware campaigns at this time. Historical Context: Type confusion vulnerabilities in WebKit have been a recurring target for sophisticated threat actors, including those conducting targeted surveillance operations against specific individuals or groups.
Remediation
- Update all Apple devices to the patched versions immediately: Safari 16.2, tvOS 16.2, macOS Ventura 13.1, iOS 15.7.2, iPadOS 15.7.2, or iOS 16.1.2 and later.
- Enable automatic software updates on all Apple devices to ensure timely application of future security patches.
- Verify patch deployment across your organization's fleet of Apple devices using mobile device management (MDM) solutions.
- If patching is not immediately possible, restrict web browsing to trusted sites and consider using network-level content filtering to reduce exposure to malicious web content.
- Monitor Apple's security advisories at https://support.apple.com for any additional guidance or follow-up patches.
- Review CISA's KEV catalog entry and ensure compliance with the remediation deadline if your organization is subject to Binding Operational Directive 22-01.
Technical Details
Vulnerability Mechanism: CVE-2022-42856 is a type confusion issue within Apple's WebKit engine. Type confusion occurs when code does not verify the type of an object before performing operations on it, leading the program to treat a memory region as a different data type than what it actually contains. In this case, maliciously crafted web content can trigger the confusion during state handling within WebKit's JavaScript or DOM processing pipeline. CVSS Vector Analysis: The CVSS:3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) with a score of 8.8 reflects a network-accessible attack with low complexity that requires no privileges but does require user interaction (visiting a malicious page). All three impact dimensions — confidentiality, integrity, and availability — are rated High, underscoring the severity of arbitrary code execution. Exploitation Pathway: An attacker crafts a webpage containing JavaScript or HTML elements designed to trigger the type confusion in WebKit's rendering or scripting engine. When a victim opens the page in Safari or any WebKit-based browser on iOS, iPadOS, macOS, or tvOS, the engine misinterprets an object's type during processing. This misinterpretation can corrupt memory structures, which the attacker leverages to redirect program execution flow and achieve arbitrary code execution within the browser's process context. Affected Components: The vulnerability affects the WebKit engine bundled with Safari 16.2 and earlier, iOS 16.1.2 and earlier, iPadOS 15.7.2 and earlier, macOS Ventura 13.1 and earlier, and tvOS 16.2 and earlier. Since WebKit is the mandatory browser engine on iOS and iPadOS, all browsers on those platforms were affected regardless of their branding.
Frequently Asked Questions
What is CVE-2022-42856?
CVE-2022-42856 is a type confusion vulnerability in Apple's WebKit browser engine that allows attackers to execute arbitrary code when a user visits a maliciously crafted webpage. It affects Safari, iOS, iPadOS, macOS Ventura, and tvOS.
How severe is CVE-2022-42856?
With a CVSS score of 8.8 (High), CVE-2022-42856 is a serious vulnerability. It requires no authentication and can be exploited remotely when a victim simply visits a malicious website, resulting in full code execution on the device.
Was CVE-2022-42856 exploited in the wild?
Yes, Apple confirmed that this vulnerability may have been actively exploited against iOS versions released before iOS 15.1. It was added to CISA's Known Exploited Vulnerabilities catalog in December 2022.
How can I fix CVE-2022-42856?
Update to Safari 16.2, iOS 15.7.2 or iOS 16.1.2, iPadOS 15.7.2, macOS Ventura 13.1, or tvOS 16.2. These updates contain Apple's fix for the type confusion issue through improved state handling.
Are all browsers on iOS affected?
Yes, because Apple requires all browsers on iOS and iPadOS to use the WebKit engine, all browsers on those platforms — including Chrome, Firefox, and others — were vulnerable until the underlying WebKit component was patched via the iOS system update.
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