CVE-2026-40378: Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.

highCVSS 7.5CVE-2026-40378

Memory allocation with excessive size value in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.5
Published: 2026-07-14
Last updated: 2026-07-16
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-40378

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-2026-403780.82% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 54% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-40378	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
highCVE-2026-40378: Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerabilitymsrc

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