CVE-2026-20857
Microsoft Windows 10 1809 ≤ 10.0.17763.8276
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-20857 is a high-severity Untrusted Pointer Dereference (CWE-822) vulnerability in Microsoft Windows 10 1809. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 39th 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 SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — 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-2026-20857, published on 2026-01-13, is an untrusted pointer dereference vulnerability (CWE-822) in the Windows Cloud Files Mini Filter Driver. This local privilege escalation flaw carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high impact potential with low complexity and low privileges required for exploitation.
An authorized attacker with local access and low privileges can exploit the untrusted pointer dereference to elevate privileges on affected Windows systems. Successful exploitation enables high confidentiality, integrity, and availability impacts, potentially allowing the attacker full control over the system.
Microsoft's Security Response Center provides details and mitigation guidance in their update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20857.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2174
Vulnerability Data
Untrusted pointer dereference in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation can discover instances where untrusted data is turned into a pointer and dereferenced.
Validating all information inputs stops untrusted values from being accepted and converted into dereferenceable pointers.
Memory-protection mechanisms limit the damage from an invalid pointer dereference without stopping the root coding flaw.
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.
Secure SDLC practices directly prevent introduction of untrusted pointer handling during development.
Runtime monitoring of software and data can detect adverse events resulting from exploitation of the weakness.
Vulnerability identification processes can discover instances of this weakness via code review or scanning.
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.
Security testing can detect pointer-dereference flaws before release.
Secure development lifecycle includes pointer-safety practices that reduce untrusted pointer dereference risk.
Application security requirements can mandate validation of pointers obtained from untrusted sources.
Secure architecture principles discourage direct use of untrusted values as pointers.
Secure coding standards explicitly forbid dereferencing pointers derived from untrusted input.