Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessDeliver crafted file via network
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DeliveryTrigger automatic file parsing in background service
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ExploitOverflow buffer in parsing routine
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ExecutionCorrupt adjacent memory structures
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ImpactLimited data disclosure or DoS
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | CRITICAL ASSESSMENT REQUIRED - CVSS vector AV:N/AC:L/PR:N/UI:N indicates no user interaction, suggesting automatic exploitation against default configurations of Apple iOS, iPadOS, and macOS when processing network-delivered files through background system services (Spotlight indexing, Quick Look, attachment handlers). However, this contradicts the description's 'parsing a maliciously crafted file' language, which typically implies user action to open or download. Verify whether affected file parsing occurs automatically for network content or requires user interaction to trigger. Exploitation is LIMITED by: device must process files from untrusted sources; specific file format must trigger vulnerable parser; macOS/iOS security mitigations (ASLR, sandboxing, PAC on Apple Silicon) increase exploitation complexity; impact constrained to low confidentiality/integrity/availability (C:L/I:L/A:L) suggesting partial compromise rather than full system control. |
| Impact | CVSS 7.3 (High) with network vector and no authentication required (AV:N/AC:L/PR:N/UI:N) suggests critical risk, but real-world exploitation probability is extremely low at EPSS 0.02% (6th percentile). This stark contrast indicates the vulnerability likely requires specific preconditions not captured in the base CVSS score. Key risk factors: The CVSS vector claims UI:N (no user interaction) yet the description states 'parsing a maliciously crafted file' - these are contradictory unless background system processes automatically parse untrusted network content without user action. The impact ratings (C:L/I:L/A:L) are modest for a memory corruption flaw, suggesting exploit reliability may be low or mitigations like ASLR/DEP remain effective. No CISA KEV listing and no public exploit identified at time of analysis despite vendor disclosure reduces immediate threat. However, Apple platforms are high-value targets and the vendor-confirmed patch indicates genuine exploitability. Priority assessment: Medium-High for organizations with Apple devices processing untrusted files from network sources, Low-Medium for isolated or highly controlled environments. The UI:N claim requires verification - if user interaction is actually required to trigger parsing, real-world risk drops significantly below CVSS suggests. |
| Exploit ScenarioDerived | Attacker hosts maliciously crafted file on web server or sends via email/messaging. When victim's device automatically processes the file through background services like Spotlight indexing, Quick Look preview generation, or attachment scanning (assuming UI:N is accurate), the out-of-bounds write corrupts memory structures. Attacker achieves limited information disclosure, integrity violation, or crashes the parsing service. With advanced exploitation techniques, could potentially achieve code execution within the sandboxed parsing context. |
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Alert meAnalysisAIv1 – May 12, 2026
Out-of-bounds write in Apple's file parsing component across iOS, iPadOS, and macOS enables remote code execution or denial of service via maliciously crafted files with no user interaction required. Exploitation probability is extremely low (EPSS 0.02%, 6th percentile) with no public exploit identified at time of analysis, despite the critical CVSS 7.3 score and network-based attack vector. Vendor patches available for all affected platforms (iOS/iPadOS 18.7.9, 26.5; macOS Sonoma 14.8.7, Sequoia 15.7.7, Tahoe 26.5). The CVSS vector indicating AV:N/PR:N/UI:N suggests automatic exploitation without user interaction, which contradicts the description's 'parsing a file' language - verify whether this requires user action to open/download the file or if background processes parse untrusted files automatically.
RemediationAI
Apply vendor-released patches immediately: upgrade iOS and iPadOS devices to version 18.7.9 or 26.5, macOS Sonoma systems to 14.8.7, macOS Sequoia systems to 15.7.7, and macOS Tahoe systems to 26.5. Installation instructions and security content details available in Apple security advisories HT127110, HT127111, HT127115, HT127116, and HT127117 at https://support.apple.com. If immediate patching is not feasible, implement network-layer filtering to block untrusted file sources and restrict automatic file parsing by disabling Quick Look previews, Spotlight indexing of untrusted directories, and background content handlers (trade-off: reduced user convenience and search functionality). On managed devices, enforce application sandboxing policies and disable automatic mounting of network shares or removable media until patching is complete (trade-off: workflow disruption for users requiring network file access). For high-security environments, consider network segmentation to isolate unpatched Apple devices from untrusted content sources until updates can be tested and deployed.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 2 packages in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
CWE-787 out-of-bounds write vulnerability in Apple's file parsing subsystem affecting iOS, iPadOS, and macOS across multiple major versions. The flaw occurs when processing file formats through system-level parsers, allowing data to be written beyond allocated buffer boundaries. Affected CPE strings indicate broad impact across Apple's mobile (cpe:2.3:a:apple:ios_and_ipados) and desktop (cpe:2.3:a:apple:macos) platforms. The vulnerability exists in a shared parsing component used across macOS Sonoma (14.x), Sequoia (15.x), and Tahoe (26.x) series, plus iOS/iPadOS 18.x and 26.x branches. Apple's fix involved improved input validation to bound-check file parsing operations, suggesting the original code lacked proper size verification when copying or writing parsed data structures. The memory corruption class (CWE-787) typically enables arbitrary code execution when combined with exploit techniques like heap spraying or ROP chains, though Apple's description conservatively lists 'unexpected app termination' as the primary impact.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Primary rating from Vendor (apple) · only source for this CVE.
CVSS VectorVendor: apple
Lifecycle Timeline
4DescriptionCVE.org
An out-of-bounds write issue was addressed with improved input validation. This issue is fixed in iOS 18.7.9 and iPadOS 18.7.9, iOS 26.5 and iPadOS 26.5, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, macOS Tahoe 26.5. Parsing a maliciously crafted file may lead to an unexpected app termination.
Executive ViewAI
CVE-2026-43656 is a high-severity out-of-bounds write vulnerability in Apple's file parsing component affecting iOS, iPadOS, and macOS that could enable remote code execution without user interaction. While Apple has released patches for all affected platforms, the extremely low exploitation probability (0.02% EPSS) and absence of public exploit code suggest immediate organizational risk is minimal; however, timely patching remains necessary to maintain security posture as the vulnerability could be leveraged by sophisticated threat actors.
Apply vendor patch. If immediate patching is constrained, restrict access to untrusted file sources and monitor for suspicious file-parsing activity; however, patch deployment should not be delayed beyond the 7-day window given network attack vector accessibility.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
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EUVD-2026-29302
GHSA-xfh5-8vfh-9mjc
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB