CVE-2026-43809: An out-of-bounds read was addressed with improved bounds checking

Q: How do I fix CVE-2026-43809?

macos: upgrade to 14.8.8, 15.7.8, 26.6. Exact commands for each OS are on this page.

Q: Is CVE-2026-43809 being exploited?

CVE-2026-43809 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-43809 affect?

CVE-2026-43809 affects macos. Severity is critical (CVSS 9.8). An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in iOS 18.7.10 and iPadOS 18.7.10, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. An app may be able to cause unexpected system termination

Q: How urgent is CVE-2026-43809?

Priority 54/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-43809 is a critical-severity flaw (CVSS 9.8) affecting macos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in iOS 18.7.10 and iPadOS 18.7.10, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. An app may be able to cause unexpected system termination.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-07-27
Last modified	2026-10-24

Publisher (CNA): Apple Inc. · Vendor: apple

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-27 21:17 UTCPublished CVE record published
2026-10-24 13:10 UTCUpdated Record last modified

apple macos UPGRADE

Affected: >= 14.0 and < 14.8.8 · >= 15.0 and < 15.7.8 · >= 26.0 and < 26.6

Fixed in: 14.8.8, 15.7.8, 26.6

Safe to downgrade to: a release before 14.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora 46 · gnome-shell-extension-tiling-assistant · FIXED · 56-1.fc46 · FEDORA-2026-ebf66a5321 · source

sudo dnf upgrade --advisory=FEDORA-2026-ebf66a5321

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43809?

macos: upgrade to 14.8.8, 15.7.8, 26.6. Exact commands for each OS are on this page.

Is CVE-2026-43809 being exploited?

CVE-2026-43809 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43809 affect?

CVE-2026-43809 affects macos. Severity is critical (CVSS 9.8). An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in iOS 18.7.10 and iPadOS 18.7.10, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. An app may be able to cause unexpected system termination

How urgent is CVE-2026-43809?

Priority 54/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Software pages

iOS vulnerabilities · macOS vulnerabilities · iPadOS vulnerabilities

Related CVEs

CVE-2026-43682 CRITICAL 9.8 UPGRADE The issue was addressed with improved memory handling
CVE-2026-64695 CRITICAL 9.8 UPGRADE The issue was addressed with improved memory handling
CVE-2026-64696 CRITICAL 9.8 UPGRADE The issue was addressed with improved memory handling
CVE-2026-28982 CRITICAL 9.8 UPGRADE A race condition was addressed with improved locking
CVE-2026-39873 CRITICAL 9.8 UPGRADE The issue was addressed with improved memory handling

References

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