A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer. The vulnerability could corrupt memory in such a way that an attacker could execute arbitrary code in the context of the current user. An attacker who successfully exploited the vulnerability could gain the same user rights as the current user. If the current user is logged on with administrative user rights, an attacker who successfully exploited the vulnerability could take control of an affected system. An attacker could then install programs; view, change, or delete data; or create new accounts with full user rights. In a web-based attack scenario, an attacker could host a specially crafted website that is designed to exploit the vulnerability through Internet Explorer and then convince a user to view the website. An attacker could also embed an ActiveX control marked "safe for initialization" in an application or Microsoft Office document that hosts the IE rendering engine. The attacker could also take advantage of compromised websites and websites that accept or host user-provided content or advertisements. These websites could contain specially crafted content that could exploit the vulnerability. The security update addresses the vulnerability by modifying how the scripting engine handles objects in memory.
Conclusion & alert: CVE-2020-1380 is rated Critical Active Threat (91.2/100): CVSS High severity, with high exploitation likelihood (EPSS 91.73%, 100th percentile). Core evidence: CISA KEV confirms active exploitation (added 2021-11-03) affecting Microsoft / Internet Explorer. a weakness (CWE-787) Unauthenticated remote administrative access may be possible. Mandatory action: The CISA remediation deadline has passed—treat as an emergency patch priority.
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: Microsoft Internet Explorer Scripting Engine Memory Corruption Vulnerability · CISA KEV detail
: 2021-11-03
: 2022-05-03
: Apply updates per vendor instructions.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-12-28 | 91.57% | 91.73% | +0.16% |
| 2 | 2025-12-27 | 91.73% | 91.57% | -0.16% |
| 3 | 2025-12-23 | — | 91.73% | — |
Full EPSS history (63 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.8 | 3.1 | HIGH |
|
1.8 | 5.9 | [email protected] |
| 8.8 | 3.1 | HIGH |
|
2.8 | 5.9 | [email protected] |
| 7.6 | 2.0 | HIGH |
|
4.9 | 10.0 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| microsoft | internet_explorer | 11 | cpe:2.3:a:microsoft:internet_explorer:11:-:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| http://packetstormsecurity.com/files/163056/Internet-Explorer-jscript9.dll-Memory-Corruption.html | Third Party Advisory VDB Entry |
| https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1380 | Patch Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1380 | US Government Resource |