CVE-2026-43656: An out-of-bounds write issue was addressed with improved input validation

Q: How do I fix CVE-2026-43656?

ipados: upgrade to 18.7.9, 26.5; iphone os: upgrade to 18.7.9, 26.5; macos: upgrade to 14.8.7, 15.7.7, 26.5. Exact commands for each OS are on this page.

Q: Is CVE-2026-43656 being exploited?

CVE-2026-43656 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-2026-43656 affect?

CVE-2026-43656 affects ipados, iphone os, macos. Severity is high (CVSS 7.3). 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 cra

Q: How urgent is CVE-2026-43656?

Priority 35/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.3REMOTEUPGRADEUPGRADEUPGRADE

CVE-2026-43656 is a high-severity flaw (CVSS 7.3) 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 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.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-787
Published	2026-05-11
Last modified	2026-10-26

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

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-11 21:19 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

apple ipados UPGRADE

Affected: < 18.7.9 · >= 26.0 and < 26.5

Fixed in: 18.7.9, 26.5

Safe to downgrade to: a release before 26.0

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.

apple iphone os UPGRADE

Affected: < 18.7.9 · >= 26.0 and < 26.5

Fixed in: 18.7.9, 26.5

Safe to downgrade to: a release before 26.0

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.

apple macos UPGRADE

Affected: >= 14.0 and < 14.8.7 · >= 15.0 and < 15.7.7 · >= 26.0 and < 26.5

Fixed in: 14.8.7, 15.7.7, 26.5

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.

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-2026-43656?

ipados: upgrade to 18.7.9, 26.5; iphone os: upgrade to 18.7.9, 26.5; macos: upgrade to 14.8.7, 15.7.7, 26.5. Exact commands for each OS are on this page.

Is CVE-2026-43656 being exploited?

CVE-2026-43656 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-2026-43656 affect?

CVE-2026-43656 affects ipados, iphone os, macos. Severity is high (CVSS 7.3). 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 cra

How urgent is CVE-2026-43656?

Priority 35/100. High severity; Remotely exploitable, no login, no user action

Software pages

iOS vulnerabilities · macOS vulnerabilities · iPadOS vulnerabilities

Related CVEs

CVE-2026-86950 HIGH 8.8 EXPLOITED UPGRADE UPGRADE Apple Multiple Products Out-of-Bounds Write Vulnerability
CVE-2026-65339 MEDIUM 5.0 UPGRADE UPGRADE A logic issue was addressed with improved checks
CVE-2026-28991 HIGH 7.5 UPGRADE UPGRADE An out-of-bounds read was addressed with improved bounds checking
CVE-2026-28864 LOW 3.3 UPGRADE UPGRADE This issue was addressed with improved permissions checking
CVE-2026-20649 HIGH 7.5 UPGRADE UPGRADE A logging issue was addressed with improved data redaction

References

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