CVE-2026-84558: A double free issue was addressed with improved memory management

Q: How do I fix CVE-2026-84558?

macos: upgrade to 27.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-84558 being exploited?

CVE-2026-84558 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-2026-84558 affect?

CVE-2026-84558 affects macos. Severity is medium (CVSS 5.5). A double free issue was addressed with improved memory management. This issue is fixed in macOS Golden Gate 27. An app may be able to cause unexpected system termination.

Q: How urgent is CVE-2026-84558?

Priority 20/100. No elevated risk signals yet.

Routine

MEDIUM 5.5UPGRADE

CVE-2026-84558 is a medium-severity flaw (CVSS 5.5) affecting macos. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A double free issue was addressed with improved memory management. This issue is fixed in macOS Golden Gate 27. An app may be able to cause unexpected system termination.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 96%)
CISA exploited list	No
Weakness	CWE-415
Published	2026-09-14
Last modified	2026-09-17

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

Last updated 2026-09-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-14 21:17 UTCPublished CVE record published
2026-09-17 17:16 UTCUpdated Record last modified

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.

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-2026-84558?

macos: upgrade to 27.0. Exact commands for each OS are on this page.

Is CVE-2026-84558 being exploited?

CVE-2026-84558 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-2026-84558 affect?

CVE-2026-84558 affects macos. Severity is medium (CVSS 5.5). A double free issue was addressed with improved memory management. This issue is fixed in macOS Golden Gate 27. An app may be able to cause unexpected system termination.

How urgent is CVE-2026-84558?

Priority 20/100. No elevated risk signals yet.

Software pages

macOS 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-2026-64767 CRITICAL 9.8 UPGRADE A buffer overflow was addressed with improved bounds checking
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

References

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