Security readout for executives and security teams
Plain-English summary
This is a Google Chrome V8 engine flaw that could let an attacker compromise a user’s browser when the user opens a crafted web page. Because CISA lists it as known exploited, vulnerable Chrome installations should be treated as urgent exposure, especially on unmanaged or slow-to-update endpoints.
Executive priority
Treat this as urgent patch compliance work. The business risk is endpoint compromise through normal web browsing, and the KEV listing means delayed remediation leaves a known exploited browser weakness in the environment.
Technical view
CVE-2021-30563 is a CWE-843 type confusion issue in V8 affecting Google Chrome before 91.0.4472.164. The CVE describes potential heap corruption through crafted HTML. CVSS 3.1 is 8.8 with network attack vector, low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is likely limited to Google Chrome installations older than 91.0.4472.164. The provided sources do not confirm other products. Highest concern is endpoints where users browse untrusted sites, receive links, or are outside managed update enforcement.
Exploitation context
CISA KEV status supports known exploitation. The supplied sources indicate exploitation would involve a crafted HTML page and user interaction. They do not provide campaign details, public exploit availability, or reliable indicators of compromise.
Researcher notes
The public bundle supports the root class, affected product, fixed-version threshold, and KEV status. The Chromium bug reference is included, but no technical detail from it is available in the bundle. Avoid inferring exploit chains, sandbox escape requirements, or downstream Chromium impact without additional vendor evidence.
Mitigation direction
- Update Google Chrome to 91.0.4472.164 or later.
- Prefer current stable Chrome, not only the minimum fixed version.
- Enforce managed browser auto-updates across endpoints.
- Prioritize unmanaged, remote, and high-risk user devices.
- Review vendor guidance if Chromium-based downstream products are in scope.
Validation and detection
- Inventory Chrome versions across managed endpoints.
- Flag any Chrome version earlier than 91.0.4472.164.
- Confirm update policy prevents rollback or stalled updates.
- Check vulnerability tooling for CISA KEV tracking of this CVE.
- Review browser security telemetry for suspicious renderer or V8 crash patterns.
Public sources used
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
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
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-843: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-30563 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/2021/07/stable-channel-update-for-desktop.htmlCVE reference · x_refsource_MISC
- https://crbug.com/1228407CVE reference · x_refsource_MISC
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30563CVE 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.
Access of Resource Using Incompatible Type ('Type Confusion')
Access of Resource Using Incompatible Type ('Type Confusion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.