CVE-2026-50303: Windows Key Guard Security Feature Bypass Vulnerability

mediumCVSS 5.5CVE-2026-50303

Use of a cryptographic primitive with a risky implementation in Windows Key Guard allows an authorized attacker to bypass a security feature locally.

CSIRTS triage

vendor: Microsoft product: Windows Key GuardOther

What: Use of a cryptographic primitive with a risky implementation in Windows Key Guard allows an authorized attacker to bypass a security feature locally.
Who is affected: Authorized users of Windows Key Guard.
Urgency: Remediation is medium urgency as it could lead to security feature bypass, but it is not currently exploited.
Action: Update to the latest version of Windows to mitigate this vulnerability.

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

⚡ Watch Windows Key Guard

Get an email when a new Windows Key Guard advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.5
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50303

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-2026-503030.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-50303	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

unknownexploitedNCSC-2026-0231 [1.00] [M/H] Vulnerabilities fixed in Microsoft Windowsncsc-nl
mediumCVE-2026-50303: Use of a cryptographic primitive with a risky implementation in Windows Key Guard allows an au…nvd

Recent advisories for Windows Key Guard

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-2026-50378: Concurrent execution using shared resource with improper synchronization ('race condition') in…nvd · 2026-07-14
mediumCVE-2026-50303: Use of a cryptographic primitive with a risky implementation in Windows Key Guard allows an au…nvd · 2026-07-14
highCVE-2026-50378: Windows Key Guard Elevation of Privilege Vulnerabilitymsrc · 2026-07-14