CVE-2026-47300: ASP.NET Core Elevation of Privilege Vulnerability

highCVSS 8.8CVE-2026-47300

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

CSIRTS triage

vendor: Microsoft product: ASP.NET Core Privilege escalation

What: Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized attacker to elevate privileges over a network.
Who is affected: Authorized users of ASP.NET Core applications.
Urgency: Remediation is urgent due to the high severity and potential for network-based privilege escalation.
Action: Patch ASP.NET Core to the latest version.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 8.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-47300

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-473000.53% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 42% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-47300	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for ASP.NET Core Elevation

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

highCVE-2026-47303: Authentication bypass by assumed-immutable data in ASP.NET Core allows an authorized attacker …nvd · 2026-07-14
highCVE-2026-47300: Incorrect implementation of authentication algorithm in ASP.NET Core allows an authorized atta…nvd · 2026-07-14
highCVE-2026-47303: ASP.NET Core Elevation of Privilege Vulnerabilitymsrc · 2026-07-14