Vulnerability · Published May 20, 2026 · Assigned by microsoft
CVE-2026-45584Microsoft Defender Remote Code Execution Vulnerability
High 8.1
In plain English
A high-severity heap buffer overflow in Microsoft Malware Protection Engine from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 58% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.9%top 41.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
Heap-based buffer overflow in Microsoft Defender allows an unauthorized attacker to execute code over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft Malware Protection Engine | 1.1.0.0 – before 1.1.26040.8 |
Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft Defender Remote Code Execution Vulnerability vendor-advisory, patch