Exploited CVEs / Apple / CVE-2026-65400

CVE-2026-65400

Apple macOS Improper Authentication Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2026-08-21 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Apple security releases, linked below.

Risk summary

CriticalCISA KEV

9.8

CVSS v3 base

9.9%

EPSS exploit probability

Critical

Severity

2026-08-18

Added to KEV

2026-08-21 (past due)

CISA due date

Actively exploited Apple macOS vulnerability, Critical severity, CVSS v3 9.8. Added to the CISA KEV catalog 2026-08-18.

CISA required action Official fix for CVE-2026-65400 Admin questions #103 hottest CVE right now

Senserva AI Opinion and rich prompt for CVE-2026-65400

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2026-65400, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2026-65400.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed once a day (early morning US Central)):
- CVE-2026-65400: Apple macOS Improper Authentication Vulnerability
- Affected: Apple macOS
- Severity: Critical, CVSS v3 9.8; EPSS 30-day exploitation probability 9.9%
- Added to CISA KEV: 2026-08-18; federal remediation due 2026-08-21
- Ransomware-linked: no
- CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or dis...
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

The fix ships from the vendor: Apple security releases.

Do this now: Federal remediation deadline 2026-08-21; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated September 3, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2026-65400

Published: 2026-08-18
Last revised: 2026-08-18
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

The strongest signal is the August 18, 2026 addition to the CISA KEV catalog, alongside Severity settling back at 9.8 after a brief drop to 0.0. Exploitation probability then climbed from 0.5% to 10.4% by August 24 before easing slightly to 9.9% on August 26, indicating sustained real-world attacker interest that still warrants urgent remediation.

Drawn by Senserva Vivid from the Senserva change record. Hover any point for its date and value.

2026-08-18 CVSS 9.8 to 0.0; CVSS 0.0 to 9.8; EPSS first scored at 0.5%; added to the CISA KEV catalog by CISA
2026-08-19 EPSS 0.5% to 0.8%
2026-08-24 EPSS 0.8% to 10.4%
2026-08-26 EPSS 10.4% to 9.9%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2026-08-21 (past due).

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Official fix for CVE-2026-65400

Update Apple macOS to version 14.8.9 or later. Update Apple macOS to version 15.7.9 or later. Update Apple macOS to version 26.6.1 or later. (Fixed-version data from NVD.)

Vendor advisory Apple security releases CISA KEV entry

Common questions about CVE-2026-65400

Is CVE-2026-65400 actively exploited?

Yes. CVE-2026-65400 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2026-08-18, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 9.9%.

What is the CISA deadline and required action for CVE-2026-65400?

CISA set the federal (BOD 22-01) remediation due date at 2026-08-21, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

What fixes CVE-2026-65400?

The authoritative fix is in the vendor advisory: see Apple security releases for the patched macOS versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2026-65400?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2026-65400's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed once a day (early morning US Central).

Scope and sources

More exploited Apple CVEs: CVE-2025-31277 CVE-2025-43520 CVE-2025-43510 CVE-2021-30952 CVE-2023-43000 CVE-2023-41974 CVE-2026-20700 CVE-2025-43529
All Apple exploited CVEs on one page: Apple vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.