VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVPublished CVSS 9.8 criticalEPSS 0.4% probability of exploitation in 30 days
Apple

CVE-2026-84520: A buffer overflow was addressed with improved size validation.

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?
0.4%

EPSS score, percentile 38.6 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
9.8 Critical

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • before 27

Versions by product

Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

What to do

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Apple macOS
StatusVersions
Affectedbefore 27

Source: CVE List, as of . About the data.

About this vulnerability

A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Golden Gate 27. A local attacker may be able to cause unexpected system termination or corrupt kernel memory.

Summary: CVE record, as of .

  • CISA has not added CVE-2026-84520 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
  • The CVE record was published on 14 Sep 2026.
  • 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 0.4% (percentile 38.6), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
  • CISA's SSVC assessment in the CVE record: exploitation none, automatable yes, technical impact total.

Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.

Description

A buffer overflow was addressed with improved size validation. This issue is fixed in macOS Golden Gate 27. A local attacker may be able to cause unexpected system termination or corrupt kernel memory.

Source: CVE List, as of . About the data.

Weakness

CWE-120
  • CWE-120: Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published
CVE record last updated

References

1

Known exploited Apple vulnerabilities

  • CVE-2026-86950: Apple Multiple Products Out-of-Bounds Write Vulnerability (added )
  • CVE-2026-65400: Apple macOS Improper Authentication Vulnerability (added )
  • CVE-2025-31277: Apple Multiple Products Buffer Overflow Vulnerability (added )
  • CVE-2025-43510: Apple Multiple Products Improper Locking Vulnerability (added )
  • CVE-2025-43520: Apple Multiple Products Classic Buffer Overflow Vulnerability (added )