CVE-2025-43209
Published: 30 July 2025
Summary
CVE-2025-43209 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Apple Macos. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 45.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mandates timely patching of the WebKit out-of-bounds access flaw, as confirmed by Apple's advisories requiring updates to fixed versions.
Requires validation of web content inputs with bounds checking to prevent out-of-bounds access during processing in Safari/WebKit.
Provides memory protections like ASLR and DEP to mitigate exploitation of the out-of-bounds access vulnerability even if triggered.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Out-of-bounds WebKit vulnerability in Safari enables remote code execution via malicious web content with no user interaction beyond browsing, directly mapping to drive-by compromise and client application exploitation.
NVD Description
An out-of-bounds access issue was addressed with improved bounds checking. This issue is fixed in iOS 18.6 and iPadOS 18.6, iPadOS 17.7.9, macOS Sequoia 15.6, macOS Sonoma 14.7.7, macOS Ventura 13.7.7, tvOS 18.6, visionOS 2.6, watchOS 11.6. Processing maliciously crafted…
more
web content may lead to an unexpected Safari crash.
Deeper analysisAI
CVE-2025-43209 is an out-of-bounds access vulnerability (CWE-787) addressed through improved bounds checking in WebKit, the browser engine used by Safari. It affects Safari on multiple Apple platforms prior to the following releases: iOS 18.6 and iPadOS 18.6, iPadOS 17.7.9, macOS Sequoia 15.6, macOS Sonoma 14.7.7, macOS Ventura 13.7.7, tvOS 18.6, visionOS 2.6, and watchOS 11.6. The issue was publicly disclosed on July 30, 2025, and carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
Remote attackers require no privileges or user interaction beyond typical web browsing and can exploit the vulnerability with low complexity by delivering maliciously crafted web content. Successful exploitation leads to an unexpected Safari crash, with the high CVSS impact metrics indicating potential for significant confidentiality, integrity, and availability disruptions.
Apple's security advisories (https://support.apple.com/en-us/124147, https://support.apple.com/en-us/124148, https://support.apple.com/en-us/124149, https://support.apple.com/en-us/124150, https://support.apple.com/en-us/124151) confirm the issue is fully mitigated by updating to the listed fixed versions across affected platforms. Security practitioners should prioritize patching all Apple devices running Safari, especially those exposed to untrusted web content.
Details
- CWE(s)