Advisory Details

December 17th, 2025

Apple Safari JavaScriptCore HashTable Expansion Integer Overflow Remote Code Execution Vulnerability

ZDI-25-1126
ZDI-CAN-28284

CVE ID CVE-2025-43501
CVSS SCORE 8.8, AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AFFECTED VENDORS Apple
AFFECTED PRODUCTS Safari
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Apple Safari. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the handling of HashTable expansion. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before writing to memory. An attacker can leverage this vulnerability to execute code in the context of the current process.

ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-ca/125892
DISCLOSURE TIMELINE
  • 2025-10-15 - Vulnerability reported to vendor
  • 2025-12-17 - Coordinated public release of advisory
  • 2025-12-17 - Advisory Updated
CREDIT Hossein Lotfi (@hosselot) of Trend Zero Day Initiative
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