CyberSecBulletin
CVE-2026-20805Exploited in the wildNVD status: Analyzed

Microsoft Windows Information Disclosure

Published Updated By the CyberSecBulletin desk

CVE-2026-20805 is a medium-severity exposure of sensitive information to an unauthorized actor vulnerability in Windows 10 Version 1607 from Microsoft, with a CVSS 3.1 base score of 5.5 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 10.0.14393.8783 as the first without the flaw, so updating Windows 10 Version 1607 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on January 13, 2026, which means attacks have been observed in the wild.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Windows 10 Version 1607 to 10.0.14393.8783 or a later version.
  2. Update Windows 10 Version 1809 to 10.0.17763.8276 or a later version.
  3. Update Windows 10 Version 21H2 to 10.0.19044.6809 or a later version.
  4. CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
  5. Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
MicrosoftWindows 10 Version 160710.0.14393.0 up to, but not including, 10.0.14393.878310.0.14393.8783
MicrosoftWindows 10 Version 180910.0.17763.0 up to, but not including, 10.0.17763.827610.0.17763.8276
MicrosoftWindows 10 Version 21H210.0.19044.0 up to, but not including, 10.0.19044.680910.0.19044.6809
MicrosoftWindows 10 Version 22H210.0.19045.0 up to, but not including, 10.0.19045.680910.0.19045.6809
MicrosoftWindows 11 version 23H210.0.22631.0 up to, but not including, 10.0.22631.649110.0.22631.6491
MicrosoftWindows 11 Version 24H210.0.26100.0 up to, but not including, 10.0.26100.762310.0.26100.7623
MicrosoftWindows 11 Version 25H210.0.26200.0 up to, but not including, 10.0.26200.762310.0.26200.7623
MicrosoftWindows Server 20126.2.9200.0 up to, but not including, 6.2.9200.258686.2.9200.25868
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0 up to, but not including, 6.2.9200.258686.2.9200.25868
MicrosoftWindows Server 2012 R26.3.9600.0 up to, but not including, 6.3.9600.229686.3.9600.22968
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0 up to, but not including, 6.3.9600.229686.3.9600.22968
MicrosoftWindows Server 201610.0.14393.0 up to, but not including, 10.0.14393.878310.0.14393.8783
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 up to, but not including, 10.0.14393.878310.0.14393.8783
MicrosoftWindows Server 201910.0.17763.0 up to, but not including, 10.0.17763.827610.0.17763.8276
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 up to, but not including, 10.0.17763.827610.0.17763.8276
MicrosoftWindows Server 202210.0.20348.0 up to, but not including, 10.0.20348.464810.0.20348.4648
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 up to, but not including, 10.0.25398.209210.0.25398.2092
MicrosoftWindows Server 202510.0.26100.0 up to, but not including, 10.0.26100.3223010.0.26100.32230
MicrosoftWindows Server 2025 (Server Core installation)10.0.26100.0 up to, but not including, 10.0.26100.3223010.0.26100.32230
MicrosoftWindows 10 1607before 10.0.14393.878310.0.14393.8783
MicrosoftWindows 10 1809before 10.0.17763.827610.0.17763.8276
MicrosoftWindows 10 21h2before 10.0.19044.680910.0.19044.6809
MicrosoftWindows 10 22h2before 10.0.19045.680910.0.19045.6809
MicrosoftWindows 11 23h2before 10.0.22631.649110.0.22631.6491
MicrosoftWindows 11 24h2before 10.0.26100.762310.0.26100.7623

Version data comes from the organisation that assigned the CVE; 2 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
NoneNothing can be modified.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (microsoft.com).

Official description

Exposure of sensitive information to an unauthorized actor in Desktop Windows Manager allows an authorized attacker to disclose information locally.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Exposure of Sensitive Information to an Unauthorized Actor

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How developers prevent this class of flaw

  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Exposure of Sensitive Information to an Unauthorized Actor vulnerabilities (CWE-200)

Timeline

  1. CVE record published.
  2. Added to CISA's Known Exploited Vulnerabilities catalogue.
  3. CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: partial).
  4. Deadline for US federal agencies to remediate, set by CISA.
  5. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Exposure of Sensitive Information to an Unauthorized Actor vulnerabilities

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