Vulnerability · Published Oct 26, 2026 · Assigned by apple
CVE-2026-84539
Critical 9.8
In plain English
A critical-severity out-of-bounds write in macOS from Apple. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.5%top 55.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in macOS Golden Gate 27, macOS Tahoe 26.7.2. An app may be able to cause unexpected system termination.
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H