Threat Intelligence / CVE / CVE-2026-65400

CVE-2026-65400 — Apple macOS

CISA KEV

CVSS v3.1 9.8 (CRITICAL) · EPSS 0.7% (higher than 52.1% of all scored CVEs) · Priority 9/10 · Published 2026-08-06

As of 2026-08-19, CVE-2026-65400 is a CRITICAL-severity vulnerability in Apple macOS, CVSS v3.1 9.8, EPSS 0.7% (52.1th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-08-18), with a US federal remediation deadline of 2026-08-21. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-65400, most recently “Apple Ships 273-CVE Coordinated Security Update Across iOS 27, macOS, watchOS, tvOS, visionOS, Safari, and Xcode — Bundles a Previously KEV-Listed Pre-Auth Screen Sharing RCE”.

Last updated: 2026-08-19

What is CVE-2026-65400?

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

The record classifies CVE-2026-65400 under weakness class CWE-287. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 43 days ago.

Severity and exploitation probability

CVSS v3.1 base score: 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST): 0.7% probability of exploitation in the next 30 days, higher than 52.1% of all scored CVEs
CISA KEV: Listed since 2026-08-18, federal remediation deadline 2026-08-21
Threadlinqs priority: 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published: 2026-08-06, last modified 2026-08-19

Is CVE-2026-65400 being exploited?

CISA added CVE-2026-65400 to the Known Exploited Vulnerabilities catalog on 2026-08-18, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-08-21 under BOD 22-01. Weaponised exploit code for CVE-2026-65400 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 58 in the Threadlinqs vulnerability feed.

HORKimhab/CVE-2026-65400 (github)

Affected products and versions

Apple: macOS

How to fix CVE-2026-65400

Vendor advisory: https://support.apple.com/en-us/148170. Because CVE-2026-65400 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-08-21. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2026-65400

2 tracked threats in the Threadlinqs corpus reference CVE-2026-65400, either in the campaign’s CVE list or as an indicator on the campaign record.

Apple Ships 273-CVE Coordinated Security Update Across iOS 27, macOS, watchOS, tvOS, visionOS, Safari, and Xcode — Bundles a Previously KEV-Listed Pre-Auth Screen Sharing RCE — CRITICAL · 2026-09-15
CVE-2026-65400: macOS Screen Sharing Authentication Bypass Grants Unauthenticated Root Access — CRITICAL · 2026-08-07

Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-08-20. This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Full detection coverage & IOCs for threats exploiting CVE-2026-65400 are available via the Threadlinqs MCP server (Purple tier). View plans →

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