CVE-2026-26131
Microsoft .Net 10.0.0 – 10.0.4
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-26131 is a high-severity Incorrect Default Permissions (CWE-276) vulnerability in Microsoft .Net. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Services File Permissions Weakness (T1574.010); ranked at the 29th 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-3 (Access Enforcement) and AC-6 (Least Privilege) — 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-2026-26131 involves incorrect default permissions in .NET, enabling an authorized attacker to elevate privileges locally. This vulnerability, associated with CWE-276, affects .NET components and 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). It was published on 2026-03-10.
A local attacker with low privileges can exploit this vulnerability with low attack complexity and no user interaction. Successful exploitation allows privilege escalation, resulting in high impacts to confidentiality, integrity, and availability.
Microsoft's update guide provides details on mitigation for CVE-2026-26131 at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26131.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-10695
Vulnerability Data
Incorrect default permissions in .NET 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
Control response
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- 11 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Enforces approved authorizations on files and resources so overly permissive defaults cannot be exploited.
Requires least-privilege defaults so that installed files are not world-writable by default.
Requires documented, restrictive configuration settings that cover file and directory permissions.
Enforces access restrictions on changes, including permission settings applied during installation or configuration.
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.
Hardened baselines and configuration management explicitly require correct default file permissions.
Defining and enforcing least-privilege access permissions directly prevents overly permissive defaults at install time.
Lifecycle management can encompass permission settings, yet the control is too broad to specifically mitigate incorrect defaults.
Secure SDLC practices include establishing secure defaults, but address only the development-phase portion of the weakness.
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.
Standard templates that restrict access to utility programs and host parameter settings prevent the assignment of overly permissive default permissions on critical resources.
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).
Windows Server 2016 (2 rules)
- V-224833 Permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-224834 Permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276
Windows Server 2019 (2 rules)
- V-205735 Windows Server 2019 permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-205736 Windows Server 2019 permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276
Windows Server 2022 (2 rules)
- V-254252 Windows Server 2022 permissions for program file directories must conform to minimum requirements. prevents CWE-276
- V-254253 Windows Server 2022 permissions for the Windows installation directory must conform to minimum requirements. prevents CWE-276