Cyber Resilience

CVE-2026-47300

Auth Bypass in Microsoft .Net 8.0.0 – 8.0.29

Published
14 July 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0053 43th percentile
Risk Priority 64 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-47300 is a high-severity Incorrect Implementation of Authentication Algorithm (CWE-303) vulnerability in Microsoft .Net. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique External Remote Services (T1133); ranked at the 43th 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 SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized attacker to elevate privileges over a network.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

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CVE-2024-43498Same product: Apple Macos
CVE-2024-43499Same product: Apple Macos
CVE-2024-43485Same product: Apple Macos
CVE-2025-8881Same product: Apple Macos
CVE-2026-50360Same vendor: Microsoft
CVE-2024-26248Same vendor: Microsoft
CVE-2026-41103Same vendor: Microsoft
CVE-2025-53782Same vendor: Microsoft
CVE-2025-21311Same vendor: Microsoft

Affected Assets

microsoft
.net
8.0.0 — 8.0.29 · 9.0.0 — 9.0.18 · 10.0.0 — 10.0.6
microsoft
visual studio 2022
17.12.0 — 17.12.22 · 17.14.0 — 17.14.36
microsoft
visual studio 2026
18.7.0 — 18.7.4

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation at post-design stages directly uncovers incorrect implementations of required authentication algorithms.

Requiring documented development processes, standards, and tools reduces the chance that an established authentication algorithm is coded incorrectly.

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.

PR.PS-06 partial match
prevents

Secure SDLC practices directly require correct implementation of authentication algorithms.

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.

degrades

Cryptography control addresses proper use of authentication algorithms but is broader than authentication alone.

prevents

Secure development lifecycle includes verification steps that can catch incorrect authentication implementations.

prevents

Application security requirements can specify correct authentication algorithm use but do not guarantee correct implementation.

prevents

Secure coding practices reduce the likelihood of incorrect authentication algorithm implementation.

finds

Security testing can detect flawed authentication implementations but does not prevent them by itself.

prevents

Secure authentication control directly requires correct implementation of authentication algorithms.

References