How severe is CVE-2021-37973?

CVE-2021-37973 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-37973 being actively exploited?

Yes. CVE-2021-37973 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-37973?

CVE-2021-37973 primarily affects Google Chrome. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-37973?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-37973 have an EU (EUVD) identifier?

Yes. CVE-2021-37973 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-24446. It is also flagged as exploited in the EUVD (since 2021-11-03).

When was CVE-2021-37973 published?

CVE-2021-37973 was published on 2021-10-08 and last updated on 2026-06-17.

CVE-2021-37973

CVE-2021-37973 is a critical-severity vulnerability in Google Chrome with a CVSS 3.x base score of 9.6. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2021-11-03). The underlying weakness is classified as CWE-416.

Key facts

Severity: Critical (CVSS 3.x base score 9.6)
CVSS v2: 6.8
EPSS exploit prediction: 12% (96th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2021-11-03)
EU (EUVD) id: EUVD-2021-24446
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2021-11-03)
Weakness: CWE-416
Affected product: Google Chrome
Published: 2021-10-08
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-37973?: 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.
How severe is CVE-2021-37973?: CVE-2021-37973 has a CVSS 3.x base score of 9.6, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-37973 being actively exploited?: Yes. CVE-2021-37973 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2021-11-03, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-37973?: CVE-2021-37973 primarily affects Google Chrome. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-37973?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-37973 have an EU (EUVD) identifier?: Yes. CVE-2021-37973 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-24446. It is also flagged as exploited in the EUVD (since 2021-11-03).
When was CVE-2021-37973 published?: CVE-2021-37973 was published on 2021-10-08 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:google:chrome:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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