Security readout for executives and security teams
This is a Chrome V8 memory-corruption flaw. A user could be compromised by opening a crafted HTML page in an affected Chrome version. Because CISA lists CVE-2021-21220 in KEV, treat it as known exploited, not a theoretical browser bug. Exposure is primarily endpoints running Google Chrome before 89.0.4389.128. Risk is higher where users browse untrusted sites, open links from email or chat, or use unmanaged browsers that may miss forced updates. Prioritize rapid closure on managed endpoints. This is a high-impact browser vulnerability with confirmed KEV status, so delayed patching leaves ordinary web browsing as a realistic business risk. Mitigation focus: Update Google Chrome to 89.0.4389.128 or later.; Apply relevant Gentoo or Fedora browser package updates where applicable.; Enforce enterprise browser update policies and block unsupported Chrome builds..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-787: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-21220 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://chromereleases.googleblog.com/2021/04/stable-channel-update-for-desktop.htmlCVE reference
- https://crbug.com/1196683CVE reference
- GLSA-202104-08CVE reference · vendor-advisory
- FEDORA-2021-c3754414e7CVE reference · vendor-advisory
- FEDORA-2021-ff893e12c5CVE reference · vendor-advisory
- FEDORA-2021-35d2bb4627CVE reference · vendor-advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21220CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.