How severe is CVE-2026-64691?

CVE-2026-64691 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-64691 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-64691?

CVE-2026-64691 affects Apple Macos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-64691?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-64691 published?

CVE-2026-64691 was published on 2026-07-27 and last updated on 2026-07-28.

CVE-2026-64691

CVE-2026-64691 is a critical-severity vulnerability in Apple Macos with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-120.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (28th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-120
Affected product: Apple Macos
Published: 2026-07-27
Last modified: 2026-07-28

Description

A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Tahoe 26.6. An app may be able to cause unexpected system termination.

Frequently asked questions

What is CVE-2026-64691?: A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Tahoe 26.6. An app may be able to cause unexpected system termination.
How severe is CVE-2026-64691?: CVE-2026-64691 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-64691 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (28th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-64691?: CVE-2026-64691 affects Apple Macos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-64691?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-64691 published?: CVE-2026-64691 was published on 2026-07-27 and last updated on 2026-07-28.

References

https://support.apple.com/en-us/128067

Affected products (1)

cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

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