CVE-2026-65398: An out-of-bounds access issue was addressed with improved bounds checking
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Routine
HIGH 7.8UPGRADEUPGRADEUPGRADE
CVE-2026-65398 is a high-severity flaw (CVSS 7.8) affecting ipados, iphone os, macos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An out-of-bounds access issue was addressed with improved bounds checking. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, watchOS 27. An app may be able to cause unexpected system termination or corrupt kernel memory.
Last updated 2026-09-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
Published CVE record published
Updated Record last modified
apple ipados UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
apple iphone os UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
apple macos UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
apple tvos UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
apple visionos UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
apple watchos UPGRADE
Affected: < 27.0
Fixed in: 27.0
Safe to downgrade to: no unaffected older release
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.
Verify at the official sourceNVD · 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-2026-65398?
ipados: upgrade to 27.0; iphone os: upgrade to 27.0; macos: upgrade to 27.0. Exact commands for each OS are on this page.
Is CVE-2026-65398 being exploited?
CVE-2026-65398 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-2026-65398 affect?
CVE-2026-65398 affects ipados, iphone os, macos. Severity is high (CVSS 7.8). An out-of-bounds access issue was addressed with improved bounds checking. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, watchOS 27. An app may be able to cause unexpected system termination or cor
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