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Apple iOS EUVDEUVD-2026-77900

| CVE-2026-84524 MEDIUM
Out-of-bounds Read (CWE-125)
2026-09-14 apple GHSA-fm7h-qp46-crpm
4.3
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
    Craft malicious font file
  2. Delivery
    Deliver to victim (document/web/message)
  3. Exploit
    Victim's app processes font
  4. Execution
    Out-of-bounds read triggered
  5. Impact
    Application unexpectedly terminates (DoS)

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK

1 technique across 1 tactic: Collection

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 process a maliciously crafted font file (UI:R) using a vulnerable Apple OS version (iOS/iPadOS <26.7 or <27, macOS <15.8/<26.7/<27, tvOS/visionOS/watchOS <27). No authentication or privileges are needed by the attacker (PR:N), but the attack is GATED on delivering the font to the victim and getting an application to parse it - the attacker cannot trigger it remotely without that interaction. Impact is limited to termination of the processing application (denial of service); there is no code execution, privilege gain, or data disclosure, which substantially limits real-world severity.

Impact

This is a genuinely low-priority issue despite the network attack vector. The vendor CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L, base 4.3) is consistent with the description: processing a maliciously crafted font file causes only unexpected app termination - a pure availability impact (A:L) with no confidentiality or integrity loss (C:N/I:N). EPSS is 0.21% (11th percentile), reinforcing very low exploitation likelihood. There is no KEV listing (not actively exploited) and no public exploit identified at time of analysis, so exploitation status is 'no public exploit identified.' The one signal worth flagging is a metadata conflict: the input Tags include 'Information Disclosure,' which directly contradicts the CVSS vector's C:N - this is an out-of-bounds READ that leaks nothing to the attacker, it only crashes the process, so the tag is mislabeled. 'Buffer Overflow' is also loose since a bounded OOB read produces termination, not code execution. Net: a real but minor denial-of-service bug requiring user interaction, correctly rated Medium/Low; not a patch-tonight priority.

Exploit ScenarioDerived

An attacker crafts a malformed font file and delivers it to a victim (embedded in a document, webpage, or message) whose Apple device parses it via the vulnerable font-handling code. When the font is processed, the out-of-bounds read triggers an unexpected termination of the affected application. No public exploit code is identified, and the impact is limited to a crash - no code execution or data disclosure.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 17, 2026

An out-of-bounds read in Apple's font-processing code can crash (terminate) an application on iOS, iPadOS, macOS, tvOS, visionOS and watchOS when it parses a maliciously crafted font file, but it cannot be used to execute code, escalate privileges, or steal data. The issue affects iOS/iPadOS before 26.7 and before 27, macOS before Sequoia 15.8, Tahoe 26.7 and Golden Gate 27, and tvOS, visionOS and watchOS before 27, and it is fixed in those listed releases; the assessed vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L, score 4.3) confirms that unauthenticated remote attackers can only succeed if a victim is induced to open or render the crafted font (user interaction required), and exploitation yields availability loss only. No public exploit code has been identified at time of analysis and the EPSS score is 0.21% (11th percentile), so real-world exploitation is unlikely; this is a genuinely low-priority issue despite the network attack vector.

RemediationAI

Vendor-released patch: iOS 26.7 and iPadOS 26.7, iOS 27 and iPadOS 27, macOS Sequoia 15.8, macOS Tahoe 26.7, macOS Golden Gate 27, tvOS 27, visionOS 27 and watchOS 27, per Apple advisories https://support.apple.com/en-us/149034 through 149043. Updating all Apple devices that consume untrusted content (mail, messaging, Safari, document viewers) is the complete fix; because the flaw is reachable through font files rendered from web pages or attachments, prioritize iPadOS/iOS and macOS endpoints exposed to external content, and note that macOS Sequoia 15.8 covers only the older branch while Tahoe 26.7 and Golden Gate 27 cover the newer ones. Where immediate upgrades are not feasible, reduce exposure by restricting the ability to install arbitrary font profiles (remove untrusted configuration profiles and disable font installation by unmanaged users), avoid opening documents or visiting pages from unverified sources on vulnerable builds, and rely on OS sandboxing/per-app isolation so a crash is contained to the rendering application - each of these is only a partial mitigation because any application that parses a font can still be terminated by a crafted file, and the trade-off is reduced functionality for users who legitimately install custom fonts. No vendor-released patch gap remains for this CVE, so no additional compensating controls are required beyond the updates listed above.

Affected VersionsENISA

watchOS 0 <27
iOS and iPadOS 0 <27
macOS 0 <15.8
visionOS 0 <27
macOS 0 <26.7
iOS and iPadOS 0 <26.7
macOS 0 <27
tvOS 0 <27

Affected Packages

euvd ios_and_ipados fix: 26.7, 27
euvd macos fix: 15.8, 26.7, 27
euvd tvos fix: 27
euvd visionos fix: 27
euvd watchos fix: 27

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 5 packages 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 a CWE-125 out-of-bounds read in the font parsing subsystem that Apple's operating systems use to interpret font files supplied by applications, documents, or downloaded content; Apple addressed it with improved bounds checking in the fixed releases. Font parsers are a classic memory-safety attack surface because they consume complex, attacker-influenceable binary formats (tables, glyph metrics, name and layout records), and a missing length check can let the parser read past the end of an allocated buffer. In this case the read is non-destructive to memory integrity: the CVSS vector AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L, consistent with the assessed vector, shows no confidentiality or integrity impact and only a low availability impact confined to the processing application, which typically manifests as unexpected app termination rather than a kernel compromise. The CPE entries (apple:ios_and_ipados, apple:macos, apple:tvos, apple:visionos, apple:watchos) confirm the defect lives in shared Apple platform code rather than a single product, which is why the same fix appears across the entire OS family in one coordinated update.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (apple) PRIMARY 4.3 MEDIUM
AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
vuln.today AI 4.3 MEDIUM

Malicious font can arrive remotely but requires the victim to open/process it (UI:R); an OOB read yields only app termination, so C:N/I:N/A:L, matching vendor 4.3.

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/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
Low

Lifecycle Timeline

4
CVSS changed
Sep 17, 2026 - 17:22 NVD
4.3 (MEDIUM)
Patch available
Sep 14, 2026 - 22:19 EUVD
CVE Published
Sep 14, 2026 - 20:50 cve.org
MEDIUM 4.3
CVE Published
Sep 14, 2026 - 20:50 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in iOS 26.7 and iPadOS 26.7, iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27, watchOS 27. Processing a maliciously crafted font file may lead to unexpected app termination.

Threat Intelligence Overview

EPSS Score
0.2%
Top 89% exploitable
Prevalence
Ubiquitous
Apple consumer OS font handling across iOS, macOS, watchOS, tvOS, visionOS
Data Quality
4 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 0.2%
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· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
High

Priority Score

22
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +22
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.

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