App termination via unsafe CoreUI memory access
Published Aug 21, 2026 · Updated Aug 21, 2026
Denial of service in Apple macOS allows remote attackers to terminate an app when a maliciously crafted file is processed. CISA maps the CoreUI issue to an out-of-bounds read and use-after-free, but published advisories identify neither the affected routine nor the failed lifetime and bounds checks. Exploitation requires the file to be processed, and the disclosed consequence is limited to app termination rather than system shutdown or data access.
Summary
What happened
Denial of service in Apple macOS allows remote attackers to terminate an app when a maliciously crafted file is processed. CISA maps the CoreUI issue to an out-of-bounds read and use-after-free, but published advisories identify neither the affected routine nor the failed lifetime and bounds checks. Exploitation requires the file to be processed, and the disclosed consequence is limited to app termination rather than system shutdown or data access.
The record
- CVE
- CVE-2026-20679
- Published
- Aug 21, 2026
- Updated
- Aug 21, 2026
- Vendor
- Apple
- Product
- macOS
- Classifications
- CWE-416, CWE-125, T1204.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 21, 2026CVE publishedPublication date reported by the CVE source.
- Aug 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <14.8.5
- Affected versionversion=0 <15.7.5
- Affected versionversion=0 <26.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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