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CVE-2021-37973

CRITICAL
9.6
CVSS Score
Published: October 8, 2021 at 09:40 PM UTC
Updated: June 17, 2026 at 04:01 AM UTC
3 products affected across 3 vendorsDebian LinuxChromeFedora

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Severity
CRITICAL9.6
Exploitation
CISA KEV
Exploit prediction
EPSS 12%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score11.7%

EPSS (Exploit Prediction Scoring System) estimates a 11.7% chance this CVE is exploited in the wild within the next 30 days — higher than 96% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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.

Required Action
Apply updates per vendor instructions.
Ransomware Use
Unknown
Added to KEV
Nov 3, 2021
Remediation Due
Nov 17, 2021
1810 days overdue
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-37973

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux· Debiandrupal
95%
10.011.0
Fedora· Fedora Projectrpm
95%
3335
Chrome· Googlenpm
95%
v < 94.0.4606.61
Affected range stops below 94.0.4606.61, so it looks safe — our inference, not a vendor statement

References (6)

x_refsource_MISCRelease Notes
Source: [email protected]
https://chromereleases.googleblog.com/2021/09/stable-channel-update-for-desktop_24.html
x_refsource_MISCIssue TrackingPatchVendor Advisory
Source: [email protected]
https://crbug.com/1251727
Vendor Advisoryx_refsource_FEDORARelease Notes
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4DDW7HAHTS3SDVXBQUY4SURELO5D4X7R/
Vendor Advisoryx_refsource_FEDORARelease Notes
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PM7MOYYHJSWLIFZ4TPJTD7MSA3HSSLV2/
Vendor Advisoryx_refsource_DEBIANMailing ListThird Party Advisory
Source: [email protected]
https://www.debian.org/security/2022/dsa-5046
US Government Resource
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-37973

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.6CRITICALCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-416

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