Authenticated code execution via LSASS use-after-free
Published Jan 13, 2026 · Updated Jan 13, 2026
Use-after-free in Microsoft Windows 11 24H2/25H2 and Server 2025 LSASS allows remote authenticated users to execute code over a network. LSASS accesses memory after releasing it, but Microsoft has not disclosed the affected routine, triggering request or protocol, or the freed object's role. Exploitation requires existing low-privileged authorization and undisclosed additional conditions; success runs attacker-controlled code in the security-critical LSASS process.
Summary
What happened
Use-after-free in Microsoft Windows 11 24H2/25H2 and Server 2025 LSASS allows remote authenticated users to execute code over a network. LSASS accesses memory after releasing it, but Microsoft has not disclosed the affected routine, triggering request or protocol, or the freed object's role. Exploitation requires existing low-privileged authorization and undisclosed additional conditions; success runs attacker-controlled code in the security-critical LSASS process.
The record
- CVE
- CVE-2026-20854
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2025 (Server Core installation)
- Classifications
- CWE-416, T1210
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 13, 2026CVE publishedPublication date reported by the CVE source.
- Jan 13, 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=10.0.26100.0 <10.0.26100.32230
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
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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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