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Apple macOS EUVDEUVD-2026-110171

| CVE-2026-113943 MEDIUM
Out-of-bounds Write (CWE-787)
2026-10-26 apple GHSA-59wp-xm42-2xm4
6.5
CVSS 3.1 · Vendor: apple
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Deliver crafted disk image to victim
  2. Exploit
    User mounts the image
  3. Execution
    Trigger out-of-bounds write in kernel
  4. Impact
    Corrupt kernel memory or crash system

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

Exploitation requires the victim to mount an attacker-supplied, maliciously crafted disk image on macOS - this user-initiated mount action (reflected as UI:R) is the specific, mandatory precondition; the flaw is not reachable without it. No authentication or elevated privileges are needed (PR:N). The limiting factors are significant: the attack is not automatable (SSVC Automatable=no), depends entirely on social engineering to get the user to mount the image, and the confirmed impact is availability only (system crash / kernel memory corruption) with no demonstrated code execution or data disclosure. Affected: all macOS versions below Golden Gate 27.2; fixed in macOS 27.2.

Impact

This is a moderate-priority issue rather than an emergency. The signals are internally consistent and all point to limited real-world risk: SSVC reports Exploitation=none, Automatable=no, and Technical Impact=partial; EPSS is low at 0.44% (38th percentile); the CVE is NOT on CISA KEV; and no public exploit or PoC reference is present in the input, so this is no public exploit identified at time of analysis. The CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H, base 6.5) is availability-only - no confidentiality or integrity impact is officially claimed - and crucially it requires user interaction (UI:R): a victim must mount the attacker-supplied disk image. One point of tension worth verifying: Apple/NVD rate this AV:N, but the actual trigger (a user locally mounting a crafted .dmg) reads as a local file-handling flaw rather than a network-service flaw, so the practical attack surface is narrower than AV:N alone suggests. The vuln.today priority of 'this_month' aligns with the low EPSS and SSVC signals - patch on a normal cycle, not as a fire drill.

Exploit ScenarioDerived

An attacker distributes a maliciously crafted disk image (e.g. via download, email, or a shared volume) and convinces a macOS user to mount it. When mounted, an out-of-bounds write (CWE-787) in the disk-image handling path corrupts kernel memory, causing unexpected system termination (denial of service) or memory corruption. No public exploit code is identified in the available data, and success depends on the user actively mounting the image (UI:R).

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 28, 2026

Apple macOS disk-image handling contains an out-of-bounds write that can corrupt kernel memory or terminate the system when a user mounts a maliciously crafted disk image. The flaw affects macOS versions before Golden Gate 27.2 and is fixed in 27.2; exploitation requires the victim to mount the crafted image (UI:R), needs no credentials (PR:N), is not automatable, and the confirmed impact is availability only, with no demonstrated code execution or data disclosure. No active exploitation is indicated and no public exploit was identified at time of analysis; EPSS is 0.44% (38th percentile), making this a moderate-priority issue rather than an emergency.

RemediationAI

Vendor-released patch: macOS Golden Gate 27.2, which Apple states fixes the out-of-bounds write through improved bounds checking; upgrade affected systems and verify the build is 27.2 or later using the Apple advisory at https://support.apple.com/en-us/149521. Until upgraded, reduce exposure by preventing users from mounting disk images obtained from untrusted or unexpected sources, since the user-initiated mount is the required trigger; this is a compensating restriction, not a complete fix, and it limits legitimate disk-image workflows. The supplied data lists no other vendor workaround, and the priority label is this_month rather than an emergency.

Affected VersionsENISA

macOS 0 <27.2

Affected Packages

euvd macos fix: 27.2

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-787, an out-of-bounds write addressed by improved bounds checking, in the code path that processes a disk image during mount. The supplied CPE cpe:2.3:a:apple:macos:*:*:*:*:*:*:*:* and EUVD range macOS 0 <27.2 identify Apple macOS below Golden Gate 27.2 as affected. The assessed vector is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H: the mount action is user-initiated and is the mandatory precondition, no authentication or elevated privileges are required, and SSVC marks the issue non-automatable with partial technical impact. The sources do not describe the exact malformed disk-image structure or which kernel component performs the unchecked write, and they do not demonstrate code execution or data disclosure.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (apple) PRIMARY 6.5 MEDIUM
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
vuln.today AI 5.5 MEDIUM

Triggered by a user locally mounting a crafted disk image (AV:L, UI:R), no privileges needed (PR:N); confirmed impact is system crash/kernel memory corruption, so A:H with C:N/I:N. (Apple/NVD rate AV:N.)

3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (apple).

CVSS VectorVendor: apple

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

4
CVSS changed
Oct 27, 2026 - 01:24 NVD
6.5 (MEDIUM)
Patch available
Oct 26, 2026 - 21:03 EUVD
CVE Published
Oct 26, 2026 - 20:40 cve.org
MEDIUM 6.5
CVE Published
Oct 26, 2026 - 20:40 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Golden Gate 27.2. Mounting a maliciously crafted disk image may cause unexpected system termination or corrupt kernel memory.

Threat Intelligence Overview

EPSS Score
0.4%
Top 62% exploitable
Prevalence
High
macOS is a major, widely-deployed desktop OS across enterprises and consumers
Data Quality
5 sources
Confidence: Medium

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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

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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