CVE-2021-37973: Google Chromium Portals Use-After-Free Vulnerability

Vulnerability summary

CVE-2021-37973 is a critical (CVSS 9.6) Use After Free vulnerability in Google Chromium Portals. It is known to be exploited: CISA lists it, first on 03-11-2021. EPSS estimates a 11.73% chance of exploitation in the next 30 days, higher than 96% of scored vulnerabilities.

Timeline

1. 08-10-2021
   PublishedVulnerability first disclosed.
2. 03-11-2021
   Added to CISA KEVGoogle Chromium Portals Use-After-Free Vulnerability
3. 17-11-2021
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

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.

• CWE-416Use After FreeThe 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.