CVE-2026-20804
Microsoft Windows 10 1607 ≤ 10.0.14393.8783
Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:NSummary
CVE-2026-20804 is a high-severity Incorrect Privilege Assignment (CWE-266) vulnerability in Microsoft Windows 10 1607. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 41th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-6 (Least Privilege) and AC-2 (Account Management) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-20804 is an incorrect privilege assignment vulnerability (CWE-266) in the Windows Hello authentication component of Microsoft Windows. Published on 2026-01-13, it carries a CVSS v3.1 base score of 7.7 (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N), indicating high severity due to its potential for significant confidentiality and integrity impacts without requiring privileges or user interaction.
The vulnerability enables a local unauthorized attacker to perform tampering on the system. Exploitation requires only local access with low attack complexity, allowing the attacker to achieve high-level access to confidential data (C:H) and modification of system integrity (I:H), though it does not affect availability (A:N).
Mitigation details are available in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20804. Security practitioners should consult this resource for patch information and recommended actions.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2197
Vulnerability Data
Incorrect privilege assignment in Windows Hello allows an unauthorized attacker to perform tampering locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 8 hardening rules · 6 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Least privilege directly requires that only the minimal necessary privileges are assigned to each actor.
Account management defines and authorizes the exact privileges granted to each account or role.
Enforces only the authorizations that were assigned, so correct assignment is a prerequisite.
Separation of duties constrains which privilege combinations may be assigned to any actor.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Directly enforces least-privilege policy definition, management, and review that prevents incorrect privilege assignments.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
The access-rights control governs the entire lifecycle of privilege assignment, directly eliminating incorrect assignments.
Privileged-access-rights control explicitly requires least-privilege assignment and ongoing validation, directly mitigating CWE-266.
Access control policy directly prevents incorrect privilege assignment by defining who may receive which rights.
Segregation of duties reduces blast radius of any single incorrect privilege but does not prevent the assignment itself.
Restricting privileged utility programs limits exposure from over-privileged accounts but does not address how privileges are assigned.
Information-access-restriction mechanisms enforce the correct privilege boundaries once assignment rules are defined.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248551 A sticky bit must be set on all OL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
Oracle Linux 9 (1 rule)
- V-271779 OL 9 must be configured so that a sticky bit must be set on all public directories. prevents CWE-266
RHEL 8 (1 rule)
- V-230243 A sticky bit must be set on all RHEL 8 public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
RHEL 9 (1 rule)
- V-257929 A sticky bit must be set on all RHEL 9 public directories. prevents CWE-266
Ubuntu 22.04 (2 rules)
- V-260513 Ubuntu 22.04 LTS must set a sticky bit on all public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266
- V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-266
Ubuntu 24.04 (2 rules)
- V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-266
- V-270750 Ubuntu 24.04 LTS must set a sticky bit on all public directories to prevent unauthorized and unintended information transferred via shared system resources. prevents CWE-266