CVE-2026-65400: Apple macOS Improper Authentication Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 18 Aug 2026, 12 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 1.7%
EPSS score, percentile 77.4 of all scored records
- How severe?
- 9.8 Critical
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
Required action (CISA), due 21 Aug 2026: 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.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected: before 14.8.9; before 15.7.9; before 26.6.1; before 26.7; before 27
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
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.
CISA due date for this action: 21 August 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- https://support.apple.com/en-us/148170
- https://support.apple.com/en-us/148171
- https://support.apple.com/en-us/148172
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- https://nvd.nist.gov/vuln/detail/CVE-2026-65400
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 14.8.9 |
| Affected | before 15.7.9 |
| Affected | before 26.6.1 |
| Affected | before 26.7 |
| Affected | before 27 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
Apple macOS contains an improper authentication vulnerability that could allow an attacker on the network to authenticate to Screen Sharing without valid credentials.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2026-65400 to its Known Exploited Vulnerabilities (KEV) catalog on 18 Aug 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 21 Aug 2026.
- The CVE record was published on 6 Aug 2026, 12 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 1.7% (percentile 77.4), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-287: Improper Authentication
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 6 Aug 2026 | CVE record published |
| 18 Aug 2026 | Added to CISA KEV |
| 21 Aug 2026 | CISA due date for the required action |
| 26 Oct 2026 | CVE record last updated |
References
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