CISA has issued an urgent warning regarding a critical zero-day vulnerability in Apple WebKit that is currently being actively exploited in attacks.
CISA has added CVE-2025-43529 to its catalog of vulnerabilities requiring immediate attention, setting a strict deadline for organizations to implement protective measures.
What Is the WebKit Vulnerability?
The vulnerability, identified as a use-after-free flaw in WebKit, affects multiple Apple products, including iOS, iPadOS, macOS, and other platforms that rely on WebKit for HTML processing.
The flaw exists in the memory management layer of the WebKit rendering engine.
| Field | Information |
|---|---|
| CVE ID | CVE-2025-43529 |
| Vulnerability Type | Use-After-Free (CWE-416) |
| Affected Products | Apple iOS, iPadOS, macOS, Safari, WebKit-based applications |
| Vulnerability Description | Use-after-free in WebKit HTML parser allowing memory corruption through maliciously crafted web content |
| Exploitation Status | Actively exploited in the wild |
Allowing attackers to manipulate memory corruption through carefully crafted malicious web content.
When users encounter these specially designed websites, the vulnerability can be triggered without additional user interaction, making it particularly dangerous.
The widespread nature of this vulnerability is concerning because it affects not only Apple’s native Safari browser but also third-party applications that integrate WebKit as their HTML rendering engine.
This significantly expands the potential attack surface across the ecosystem.
The vulnerability is classified as a use-after-free condition, which falls under CWE-416, meaning attackers could potentially achieve arbitrary code execution on vulnerable systems.
CISA has emphasized that all organizations and users should apply security updates from Apple immediately upon availability.
The agency has set a mandatory compliance deadline of January 5, 2026, for federal agencies and contractors under the Binding Operational Directive (BOD) 22-01 framework.
In cloud service environments, organizations must follow their service providers’ applicable guidance and implement compensating controls where necessary.
Users are advised to enable automatic security updates on all Apple devices to ensure they receive patches as soon as they are released.
Organizations should inventory all systems that use WebKit-based browsers and applications and prioritize patching accordingly.
For systems where immediate patching is not feasible, administrators should consider restricting web browsing to trusted sites only and implementing network-based filtering of malicious content.
Security researchers continue to investigate the scope and full implications of this vulnerability. Apple will release additional details regarding patched versions and remediation guidance through official security advisories.
Organizations should monitor CISA alerts and Apple’s security updates page regularly for the latest information.
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