Description

An out-of-bounds access issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.10 and iPadOS 18.7.10, iOS 26.6.1 and iPadOS 26.6.1, macOS Tahoe 26.6.2. Processing maliciously crafted web content may lead to an unexpected Safari crash.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.3",
  "pubDate": "2026-08-17T22:17:23.273Z",
  "pubdate": "2026-08-17T22:17:23.273Z",
  "executiveSummary": "An out-of-bounds access vulnerability has been identified within the web content processing capabilities of Safari, impacting multiple Apple operating system versions. This security defect arises from insufficient bounds checking when parsing or rendering maliciously crafted web content. Successful exploitation of this vulnerability can lead to an unexpected application crash, resulting in a localized denial of service for the Safari browser.\nThe affected systems include iOS 18.7.10, iPadOS 18.7.10, iOS 26.6.1, iPadOS 26.6.1, and macOS Tahoe 26.6.2. The risk implications are primarily associated with service availability and potential application instability rather than arbitrary code execution or direct system compromise. However, threat actors can leverage this flaw to disrupt user sessions by forcing browser termination.\nThe attacker capabilities require the ability to deliver or host maliciously crafted web content, typically requiring a victim to navigate to a compromised or attacker-controlled website. No specific authentication or high-level privileges are required by the attacker to initiate the exploitation vector, as the trigger relies entirely on the client-side parsing of untrusted input by the vulnerable browser engine components.",
  "technicalDetails": "The vulnerability is fundamentally rooted in an out-of-bounds access flaw caused by inadequate bounds checking within the data processing routines of the Safari web rendering engine. When the browser attempts to process maliciously crafted web content—such as specially formatted Hypertext Markup Language (HTML), Cascading Style Sheets (CSS), or embedded scripting components—it fails to properly validate input sizes and buffer boundaries prior to memory read or write operations.\nThe affected component is responsible for handling complex web content structures. Without rigorous validation of offsets and length parameters against allocated buffer limits, the processing engine attempts to access memory addresses outside of the designated buffer allocation. This boundary violation triggers an immediate memory access exception.\nThe attack flow proceeds as follows: First, an attacker constructs a maliciously crafted web page containing specific payloads designed to target the inadequate bounds checking logic. Second, the victim utilizes Safari to access the malicious URL or view content supplied via an untrusted source. Third, the browser's rendering engine parses the malicious input structures. Fourth, during the parsing phase, an out-of-bounds memory access occurs because the input parameters exceed expected constraints. Finally, the exception handling mechanism encounters the invalid memory reference, causing an unhandled fault and resulting in an unexpected Safari crash.\nRegarding environmental and access constraints, the vulnerability can be triggered remotely over the network via standard web browsing vectors. Authentication and elevated privileges are not required to induce the crash, as the flaw is triggered entirely through the client-side interpretation of untrusted web data. The post-exploitation impact is strictly confined to the termination of the Safari application process, preventing further interaction within the affected session until the browser is restarted."
}