LiveActive security incident?Get immediate response
CVE Record

CVE-2021-4323: Insufficient validation of untrusted input in Extensions in Google Chrome prior to 90.0.4430.72 allowed an...

Insufficient validation of untrusted input in Extensions in Google Chrome prior to 90.0.4430.72 allowed an attacker who convinced a user to install a malicious extension to access local files via a crafted Chrome Extension. (Chromium security severity: Medium)

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Chrome issue let a malicious extension access local files if an attacker persuaded a user to install it. The business risk is mainly endpoint data exposure through browser extensions, not a remotely exploitable server flaw. Google fixed it in Chrome 90.0.4430.72, and Chromium rated it Medium severity.

Executive priority

Treat as a routine but real endpoint hardening item. Prioritize updating outdated browsers and controlling extension installation, especially on systems handling sensitive files. It is not supported as actively exploited in the provided sources.

Technical view

CVE-2021-4323 is insufficient validation of untrusted input in Chrome Extensions before 90.0.4430.72. The reported impact is local file access through a crafted Chrome extension after malicious extension installation. The bundle provides no CVSS vector, CWE, or detailed root-cause notes, and the Chromium bug may not expose full technical detail publicly.

Likely exposure

Exposure is most likely on managed or unmanaged endpoints running Chrome or Chromium builds older than 90.0.4430.72, especially where users can install extensions without approval.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. The stated attacker requirement is convincing a user to install a malicious extension, so exploitation depends on extension installation and user interaction.

Researcher notes

Public details are limited. The key validated elements are the affected Chrome Extensions component, pre-90.0.4430.72 versions, malicious-extension precondition, local-file access impact, and Chromium Medium severity. Avoid assuming broader sandbox escape, remote code execution, or active exploitation without additional evidence.

Mitigation direction

  • Update Chrome or Chromium to 90.0.4430.72 or later.
  • Confirm Linux distributions have applied their Chromium security package updates.
  • Restrict extension installation to approved, managed extension allowlists.
  • Remove unknown, unnecessary, or user-installed extensions from managed endpoints.
  • Check current Google and OS vendor guidance for any additional actions.

Validation and detection

  • Inventory Chrome and Chromium versions across endpoints.
  • Flag browsers older than 90.0.4430.72 for remediation.
  • Review enterprise extension policies for unmanaged installation paths.
  • Audit installed extensions for unapproved or suspicious entries.
  • Verify browser updates completed through endpoint management telemetry.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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.

cve · low confidence lookup

CVE-2021-4323 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

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.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
GoogleChrome90.0.4430.72Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.