Microsoft Windows
CVE-2020-1259 — Windows Host Guardian Service Security Feature Bypass Vulnerability
Executive Summary
A security feature bypass vulnerability exists when Windows Host Guardian Service improperly handles hashes recorded and logged. An attacker who successfully exploited the vulnerability could tamper with the log file. In an attack scenario, an attacker can change existing event log types to a type the parsers do not interpret allowing an attacker to append their own hash without triggering an alert. The update addresses the vulnerability by correcting how Windows Host Guardian Service handles logging of the measured boot hash.
Overview
4.3
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
Low
INTEGRITY
None
AVAILABILITY
None
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 3.9
EPSS Score
0.03126
probability of exploitation in the next 30 days
0.86178 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
30 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 10 for 32-bit Systems | 4561649 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 for x64-based Systems | 4561649 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1607 for 32-bit Systems | 4561616 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1607 for x64-based Systems | 4561616 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1709 for 32-bit Systems | 4561602 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1709 for ARM64-based Systems | 4561602 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1709 for x64-based Systems | 4561602 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1803 for 32-bit Systems | 4561621 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1803 for ARM64-based Systems | 4561621 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1803 for x64-based Systems | 4561621 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1809 for 32-bit Systems | 4561608 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1809 for ARM64-based Systems | 4561608 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1809 for x64-based Systems | 4561608 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1903 for 32-bit Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1903 for ARM64-based Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1903 for x64-based Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1909 for 32-bit Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1909 for ARM64-based Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 1909 for x64-based Systems | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 2004 for 32-bit Systems | 4557957 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 2004 for ARM64-based Systems | 4557957 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows 10 Version 2004 for x64-based Systems | 4557957 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2016 | 4561616 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2016 (Server Core installation) | 4561616 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2019 | 4561608 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server 2019 (Server Core installation) | 4561608 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 1803 (Server Core Installation) | 4561621 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 1903 (Server Core installation) | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 1909 (Server Core installation) | 4560960 (Security Update) |
Important | Security Feature Bypass | Yes |
| Windows Server, version 2004 (Server Core installation) | 4557957 (Security Update) |
Important | Security Feature Bypass | Yes |
Patches
7 patches
| Article | Type | Restart |
|---|---|---|
4561649 |
Security Update | Yes |
4561616 |
Security Update | Yes |
4561602 |
Security Update | Yes |
4561621 |
Security Update | Yes |
4561608 |
Security Update | Yes |
4560960 |
Security Update | Yes |
4557957 |
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
Eric Chiang of Google
References
On This Page