<p>A remote code execution vulnerability exists in the way that Microsoft browsers access objects in memory. The vulnerability could corrupt memory in a way that could allow an attacker to 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, the attacker 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.</p> <p>An attacker could host a specially crafted website that is designed to exploit the vulnerability through Microsoft browsers, and then convince a user to view the website. The attacker could also take advantage of compromised websites, or websites that accept or host user-provided content or advertisements, by adding specially crafted content that could exploit the vulnerability. In all cases, however, an attacker would have no way to force users to view the attacker-controlled content. Instead, an attacker would have to convince users to take action, typically via an enticement in email or instant message, or by getting them to open an email attachment.</p> <p>The security update addresses the vulnerability by modifying how Microsoft browsers handle objects in memory.</p>
Conclusion & alert: CVE-2020-0878 is rated Active Exploitation (70/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.70%). Core evidence: CISA KEV confirms active exploitation (added 2021-11-03) affecting Microsoft / Edge and 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.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
: Microsoft Edge and Internet Explorer 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 | 2026-06-15 | 5.27% | 2.70% | -2.57% |
| 2 | 2026-03-01 | 9.82% | 5.27% | -4.55% |
| 3 | 2025-12-28 | — | 9.82% | — |
Full EPSS history (57 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 4.2 | 3.1 | MEDIUM |
|
1.6 | 2.5 | [email protected] |
| 7.5 | 3.1 | HIGH |
|
1.6 | 5.9 | [email protected] |
| 5.1 | 2.0 | MEDIUM |
|
4.9 | 6.4 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| microsoft | internet_explorer | 11 | cpe:2.3:a:microsoft:internet_explorer:11:-:*:*:*:*:*:* |
| microsoft | internet_explorer | 9 | cpe:2.3:a:microsoft:internet_explorer:9:*:*:*:*:*:*:* |
| microsoft | edge | — | cpe:2.3:a:microsoft:edge:-:*:*:*:*:*:*:* |
| microsoft | chakracore | — | cpe:2.3:a:microsoft:chakracore:-:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-0878 | Patch Vendor Advisory |
| https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-0878 | US Government Resource |