CVE-2025-43343
Published: 15 September 2025
Summary
CVE-2025-43343 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Apple Safari. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Drive-by Compromise (T1189); ranked at the 44.1th 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-16 (Memory Protection) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly requires timely patching and remediation of known flaws like CVE-2025-43343's memory handling vulnerability fixed in updated Safari and OS versions.
Implements memory safeguards such as address space randomization and non-executable data to comprehensively mitigate CWE-119 buffer overflow exploits during web content processing.
Validates maliciously crafted web content inputs to restrict operations that could trigger the memory handling vulnerability in WebKit.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Memory corruption in WebKit/Safari enables drive-by browser exploitation (T1189) leading to client-side code execution (T1203) via malicious web content.
NVD Description
The issue was addressed with improved memory handling. This issue is fixed in Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, watchOS 26. Processing maliciously crafted web content may lead to an unexpected process…
more
crash.
Deeper analysisAI
CVE-2025-43343 is a memory handling vulnerability classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer). It affects Apple's Safari browser and WebKit rendering engine across multiple platforms, including Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. The issue arises when processing maliciously crafted web content, which may lead to an unexpected process crash. The vulnerability 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), marking it as critical.
Any remote attacker can exploit this vulnerability without authentication, privileges, or user interaction, simply by having a targeted user load malicious web content in an affected browser or app. Exploitation occurs over the network with low complexity, potentially granting high impacts on confidentiality, integrity, and availability as scored by CVSS, despite the described outcome of a process crash.
Apple has addressed the vulnerability through improved memory handling in the listed fixed versions of Safari 26, iOS 26 and iPadOS 26, macOS Tahoe 26, tvOS 26, visionOS 26, and watchOS 26. Security practitioners should ensure systems are updated to these versions. Additional details are provided in Apple's security advisories at https://support.apple.com/en-us/125108, https://support.apple.com/en-us/125110, https://support.apple.com/en-us/125113, https://support.apple.com/en-us/125114, and https://support.apple.com/en-us/125115.
Details
- CWE(s)