CVE-2026-21513

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National Vulnerability Database Information

Description: Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network.

CVSS Base Score: 8.8 (v3.1)

The **CVSS Base Score** is a score from **0 to 10** that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.

Value

0.02.55.07.510.0

Published on: 02/10/2026 18:16:33
Last modified: 02/10/2026 21:51:48
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

Base Severity: HIGH
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector: NETWORK
Attack Complexity: LOW
Privileges Required: NONE
User Interaction: REQUIRED
Scope: UNCHANGED
Confidentiality Impact: HIGH
Integrity Impact: HIGH
Availability Impact: HIGH

Common Weakness Enumeration (CWE)

Database CWE: v4.18

CWE-693: Protection Mechanism Failure ↗

The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

Fonte: MITRE CWE

FIRST Information

EPSS Score: N/A

The **EPSS (Exploit Prediction Scoring System)** is a score from **0 to 1** that indicates the **probability** that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.

EPSS Score not available for this CVE.

Percentile: N/A

The **Percentile** indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.

Percentile not available for this CVE.

*Data updated as of: N/A

CISA Information (Known Exploited Vulnerabilities)

The **CISA KEV Catalog** lists vulnerabilities that have been **actively exploited in the real world**. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.

CVE **CVE-2026-21513** **IS PRESENT** in the CISA KEV Catalog!

Vulnerability Name: Microsoft MSHTML Framework Protection Mechanism Failure Vulnerability
Short Description: Microsoft MSHTML Framework contains a protection mechanism failure vulnerability that could allow an unauthorized attacker to bypass a security feature over a network.
Date Added to KEV: 02/10/2026
Vendor/Product: Microsoft / Windows
Required Action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Due Date: 03/03/2026