Security Vulnerability CVE-2021-37973 - Complete Analysis and Details

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CVE-2021-37973

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National Vulnerability Database Information

Description: Use after free in Portals in Google Chrome prior to 94.0.4606.61 allowed a remote attacker who had compromised the renderer process to potentially perform a sandbox escape via a crafted HTML page.

CVSS Base Score: 9.6 (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: 10/08/2021 22:15:08
Last modified: 10/24/2025 21:08:10
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

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

Common Weakness Enumeration (CWE)

Database CWE: v4.18

CWE-416: Use After Free ↗

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Fonte: MITRE CWE

FIRST Information

EPSS Score: 0.0666

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.

Value

0.00.250.50.751.0

Percentile: 0.9085

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.

Value

0.00.250.50.751.0

*Data updated as of: 2025-12-08

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-2021-37973** **IS PRESENT** in the CISA KEV Catalog!

Vulnerability Name: Google Chromium Portals Use-After-Free Vulnerability
Short Description: Google Chromium Portals contains a use-after-free vulnerability that allows a remote attacker, who has compromised the renderer process, to potentially perform a sandbox escape via a crafted HTML page. This vulnerability affects web browsers that utilize Chromium, including Google Chrome and Microsoft Edge.
Date Added to KEV: 11/03/2021
Vendor/Product: Google / Chromium Portals
Required Action: Apply updates per vendor instructions.
Due Date: 11/17/2021

Articles published on Red Hot Cyber

NVD References

Exploit PoC from GitHub

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