Windows Local Security Authority Subsystem Service (LSASS)
CVE-2026-20854 — Windows Local Security Authority Subsystem Service (LSASS) Remote Code Execution Vulnerability
Executive Summary
Use after free in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to execute code over a network.
Overview
7.5
CVSS HIGH
Critical
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.5
EPSS Score
0.01044
probability of exploitation in the next 30 days
0.5965 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
6 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 11 Version 24H2 for ARM64-based Systems | 5074109 (Security Update) |
Critical | Remote Code Execution | Yes |
| Windows 11 Version 24H2 for x64-based Systems | 5074109 (Security Update) |
Critical | Remote Code Execution | Yes |
| Windows 11 Version 25H2 for ARM64-based Systems | 5074109 (Security Update) |
Critical | Remote Code Execution | Yes |
| Windows 11 Version 25H2 for x64-based Systems | 5074109 (Security Update) |
Critical | Remote Code Execution | Yes |
| Windows Server 2025 | 5073379 (Security Update) |
Critical | Remote Code Execution | Yes |
| Windows Server 2025 (Server Core installation) | 5073379 (Security Update) |
Critical | Remote Code Execution | Yes |
Patches
2 patches
| Article | Type | Restart |
|---|---|---|
5074109 |
Security Update | Yes |
5073379 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Howard McGreehan with MSRC V&M
References
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