CVE-2019-8506
Apple Multiple Products Type Confusion Vulnerability
Description
CVE-2019-8506 is a type confusion vulnerability affecting multiple Apple products through the WebKit browser engine. This security flaw allows a remote attacker to achieve arbitrary code execution by luring a victim into processing maliciously crafted web content. The type confusion issue in WebKit leads to incorrect handling of JavaScript objects, resulting in memory corruption that can be weaponized for code execution. CISA has confirmed active exploitation of CVE-2019-8506 in the wild by adding it to the Known Exploited Vulnerabilities catalog with a remediation deadline of May 25, 2022. The EPSS percentile of approximately 92% indicates a very high probability of exploitation, underscoring the urgency of patching.
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 | icloud | < 7.11 |
| apple | itunes | < 12.9.4 |
| apple | safari | < 12.1 |
| apple | iphone os | < 12.2 |
| apple | tvos | < 12.2 |
| apple | watchos | < 5.2 |
| redhat | enterprise linux desktop | 7.0 |
| redhat | enterprise linux server | 7.0 |
| redhat | enterprise linux workstation | 7.0 |
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
- https://support.apple.com/HT209599(Release Notes, Vendor Advisory)
- https://support.apple.com/HT209601(Release Notes, Vendor Advisory)
- https://support.apple.com/HT209602(Release Notes, Vendor Advisory)
- https://support.apple.com/HT209603(Release Notes, Vendor Advisory)
- https://support.apple.com/HT209604(Release Notes, Vendor Advisory)
- https://support.apple.com/HT209605(Release Notes, Vendor Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-8506(US Government Resource)
Weakness Type
Type Confusion
The type confusion vulnerability in Apple WebKit arises when the JavaScript engine processes an object using a type that is incompatible with its actual memory representation. In CVE-2019-8506, WebKit mishandles type information during the execution of crafted JavaScript, causing it to treat memory as a different type than what was originally allocated, leading to heap corruption and arbitrary code execution.
Learn more: CWE-843 — Access of Resource Using Incompatible Type (Type Confusion)
Impact Analysis
CVE-2019-8506 poses a significant risk to all Apple platforms that rely on WebKit for rendering web content, including Safari, iOS, iPadOS, macOS, watchOS, and tvOS. The vulnerability is remotely exploitable over the network without requiring any authentication from the attacker, though user interaction is needed in the form of visiting a malicious website or opening crafted web content. Successful exploitation enables arbitrary code execution, which can compromise the confidentiality of sensitive data on the device, allow modification of system files and installed applications, and disrupt device availability through crashes or persistent exploitation. The EPSS percentile of approximately 92% places this vulnerability among the most likely to be exploited, and its inclusion in CISA's KEV catalog confirms that threat actors are actively leveraging this flaw in real-world attacks.
Exploit Maturity
CISA has confirmed active exploitation of CVE-2019-8506 in the wild by including it in the Known Exploited Vulnerabilities catalog with a remediation deadline of May 25, 2022. The EPSS percentile of approximately 92% indicates near-certain exploitation activity, placing this vulnerability in the top tier of actively exploited flaws. The high EPSS score combined with the KEV listing strongly suggests that mature, reliable exploits exist in the hands of threat actors targeting unpatched Apple devices through malicious web content.
Remediation
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Apply Apple security updates immediately as required by CISA: "Apply updates per vendor instructions." Update all affected Apple products including Safari, iOS, iPadOS, macOS, watchOS, and tvOS to versions that contain the WebKit type confusion fix.
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Prioritize patch deployment across all managed Apple devices using Mobile Device Management (MDM) solutions. Given the 92% EPSS percentile, this vulnerability should be treated as a top-priority patch, with emergency deployment windows if standard patch cycles have not yet addressed it.
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Implement web content filtering and DNS-based protection to block access to known malicious domains and reduce the likelihood of users encountering exploit pages. Deploy network-level controls such as web proxies and secure DNS resolvers to intercept malicious web traffic.
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Monitor for indicators of compromise by reviewing endpoint logs for unusual WebKit or Safari process behavior, unexpected child processes spawned by browser applications, memory corruption indicators, and signs of unauthorized code execution or data exfiltration after browsing sessions.
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Deploy browser isolation solutions for high-value targets and sensitive environments to contain potential WebKit exploitation. Browser isolation ensures that even if a type confusion exploit is triggered, the malicious code executes in an isolated environment rather than on the user's device.
Technical Details
CVE-2019-8506 is a type confusion vulnerability in Apple's WebKit browser engine that affects the JavaScript execution pipeline. Type confusion occurs when WebKit's JavaScript engine allocates an object with one type but subsequently accesses it using an incompatible type, leading to out-of-bounds memory access and heap corruption. The vulnerability can be triggered remotely when a victim processes specially crafted web content, requiring no authentication from the attacker but necessitating user interaction such as clicking a link or visiting a malicious page. Once the type confusion is exploited, an attacker can achieve arbitrary read/write primitives within the WebKit renderer process, enabling full arbitrary code execution on the affected Apple device through careful manipulation of JavaScript engine internals.
Frequently Asked Questions
Is CVE-2019-8506 being actively exploited?
Yes, CVE-2019-8506 is being actively exploited in the wild. CISA has added this vulnerability to the Known Exploited Vulnerabilities catalog with a remediation deadline of May 25, 2022. The EPSS percentile of approximately 92% indicates a very high probability of exploitation.
What products are affected by CVE-2019-8506?
CVE-2019-8506 affects multiple Apple products that use the WebKit browser engine, including Safari, iOS, iPadOS, macOS, watchOS, and tvOS. Any application on Apple platforms that renders web content through WebKit is potentially vulnerable to this type confusion flaw.
How do I fix CVE-2019-8506?
Apply the latest security updates from Apple for all affected products immediately. Use MDM solutions to verify patch deployment across managed devices. As an interim measure, implement web content filtering and browser isolation to reduce exposure to malicious web content.
How severe is CVE-2019-8506?
CVE-2019-8506 is a high-severity vulnerability enabling arbitrary code execution through malicious web content. With an EPSS percentile of approximately 92% and confirmed active exploitation in the KEV catalog, this is one of the most critical WebKit vulnerabilities requiring immediate patching across all Apple devices.
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