CVE-2026-86973 in iOS
Summary
by MITRE • 10/26/2026
An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in Safari 27.2, iOS 26.7.2 and iPadOS 26.7.2, iOS 27.2 and iPadOS 27.2, macOS Golden Gate 27.2. Processing maliciously crafted web content may lead to an unexpected process crash.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability described constitutes a classic out-of-bounds read condition within the rendering engine of Safari and associated Apple operating systems including iOS, iPadOS, and macOS. This type of flaw typically arises when software accesses memory locations that lie outside the intended buffer boundaries, reading data from adjacent memory spaces rather than the allocated resource. In the context of web browsers, this often occurs during the parsing or execution of complex HTML, CSS, JavaScript, or multimedia content where input validation is insufficient. The root cause lies in a failure to properly verify array indices or pointer offsets before accessing memory, allowing an attacker who controls the crafted web content to trigger access to unauthorized memory regions. This aligns directly with CWE-125, which defines out-of-bounds read as reading data beyond the end of a buffer, potentially leading to information disclosure or denial of service depending on what is accessed and how it is handled by the application logic.
The operational impact of this vulnerability centers primarily on stability and availability rather than immediate remote code execution, although the latter remains a latent risk if the leaked memory contents are manipulated further in subsequent processing steps. As noted in the advisory, processing maliciously crafted web content may lead to an unexpected process crash. This indicates that while the initial flaw is a read operation, the consequence manifests as a denial of service through application termination. An attacker could host a specially constructed webpage or embed malicious elements within legitimate sites visited by users with outdated software versions. When such content is rendered, the browser attempts to access memory it does not own, triggering an exception that forces the browser process to terminate abruptly. This disrupts user productivity and can be exploited in targeted attacks to degrade service availability for specific targets using older operating system versions like iOS 26.7.1 or earlier, iPadOS 26.7.1 or earlier, macOS Golden Gate 27.1 or earlier, Safari 27.1 or earlier, as well as the legacy iOS 27.1 and iPadOS 27.1 releases which are no longer receiving this specific patch in their current state without upgrading to the newer major version branches mentioned.
From a threat intelligence perspective, this vulnerability maps to MITRE ATT&CK technique T1499, Endpoint Denial of Service, specifically under sub-techniques involving application crash or resource exhaustion via memory corruption. While out-of-bounds reads are frequently associated with information disclosure CWE-200 where sensitive data from adjacent heap structures might be leaked back to the attacker through side channels or subsequent display operations, the primary reported impact here is stability degradation. However security researchers must remain vigilant because modern browser engines often have complex state machines that may process read memory in ways that could lead to further exploitation vectors if not properly sanitized by the operating system's memory protection mechanisms such as ASLR and DEP which mitigate but do not eliminate all risks associated with memory corruption flaws.
Mitigation for this vulnerability requires strict adherence to patch management policies across Apple ecosystems. Users running iOS 26.7.1, iPadOS 26.7.1, macOS Golden Gate 27.1 or earlier must update their devices immediately to the fixed versions listed in the advisory which include Safari 27.2, iOS 26.7.2 and iPadOS 26.7.2 as well as the newer major release branches iOS 27.2 and iPadOS 27.2 along with macOS Golden Gate 27.2. These updates contain improved bounds checking logic that validates memory access requests against allocated buffer sizes before execution, thereby preventing unauthorized reads. For organizations managing large fleets of Apple devices, deploying these updates via Mobile Device Management solutions is critical to reduce the attack surface exposed by web-based threats. Additionally users should exercise caution when visiting untrusted websites or opening suspicious email attachments containing embedded media until their systems are fully patched as no reliable workaround exists other than updating the software itself since browser sandboxing alone cannot prevent all memory corruption vulnerabilities from causing crashes even if it limits privilege escalation potential.