Local privilege escalation via EFS heap overflow
Published Sep 8, 2026 · Updated Sep 10, 2026
Heap-based buffer overflow in Microsoft Windows EFS allows local authenticated users to elevate privileges on affected systems. Microsoft has not disclosed the EFS routine, attacker-controlled input, or bounds-check failure that produces the heap overwrite. Low-privileged local access is required, and successful exploitation crosses a privilege boundary without any reported remote attack path.
Summary
What happened
Heap-based buffer overflow in Microsoft Windows EFS allows local authenticated users to elevate privileges on affected systems. Microsoft has not disclosed the EFS routine, attacker-controlled input, or bounds-check failure that produces the heap overwrite. Low-privileged local access is required, and successful exploitation crosses a privilege boundary without any reported remote attack path.
The record
- CVE
- CVE-2026-69841
- Published
- Sep 8, 2026
- Updated
- Sep 10, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-122, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 10, 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=10.0.17763.0 <10.0.17763.9245
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.
Weakness, pattern, technique
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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