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CVE-2026-65400

Apple macOS Improper Authentication

9.8 CRITICALActively exploited (CISA KEV)EPSS 1.72%
  1. Published6 Aug 2026
  2. Added to CISA KEV18 Aug 2026
  3. Remediation due21 Aug 2026
Actively exploited (CISA KEV)

Apple macOS contains an improper authentication vulnerability that could allow an attacker on the network to authenticate to Screen Sharing without valid credentials.

Added to KEV: 18 Aug 2026Federal remediation due: 21 Aug 2026

Description

An authentication issue was addressed with improved state management. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.7.9, macOS Sonoma 14.8.9, macOS Tahoe 26.6.1, macOS Tahoe 26.7. An attacker on the network may be able to authenticate to Screen Sharing without valid credentials.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Apple macOS≥ 14.0 < 14.8.9 · ≥ 15.0 < 15.7.9 · ≥ 26.0 < 26.6.1

Remediation

Fixed in
Apple macOS≥ 14.8.9

References

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Frequently asked

Is CVE-2026-65400 being actively exploited?

Yes. CVE-2026-65400 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 18 Aug 2026.

How severe is CVE-2026-65400?

CVE-2026-65400 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 1.72% probability of exploitation.

Which products are affected by CVE-2026-65400?

Affected products include Apple macOS.

How do I fix CVE-2026-65400?

Upgrade affected software to a fixed version, for example Apple macOS 14.8.9 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-65400 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.