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CVE-2021-30511: Out of bounds read in Tab Groups in Google Chrome prior to 90.0.4430.212 allowed an attacker who convinced...

Out of bounds read in Tab Groups in Google Chrome prior to 90.0.4430.212 allowed an attacker who convinced a user to install a malicious extension to perform an out of bounds memory read via a crafted HTML page.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Chrome flaw could let an attacker read browser memory if they first convinced a user to install a malicious extension and then open crafted HTML. Risk depends on outdated Chrome or Chromium builds and extension controls. The provided sources identify Chrome before 90.0.4430.212 as affected and do not show active exploitation.

Executive priority

Treat this as a patch-compliance and browser-hardening issue, not an emergency based on the provided evidence. Prioritize any unmanaged endpoints, outdated Chromium packages, and teams with permissive extension installation policies.

Technical view

CVE-2021-30511 is an out-of-bounds read in Chrome Tab Groups. The described attack path requires a malicious extension plus crafted HTML, allowing an out-of-bounds memory read. The bundle does not provide CVSS, CWE, or public bug detail, so technical assessment is limited to version exposure and extension-install control posture.

Likely exposure

Organizations are mainly exposed where Google Chrome or Chromium-derived distro packages remained below 90.0.4430.212, especially where users can install untrusted extensions. Managed fleets with current browser patching and restricted extension policies have materially lower exposure.

Exploitation context

The source bundle says exploitation requires convincing a user to install a malicious extension and interact with crafted HTML. CISA KEV is false, and no cited source in the bundle reports active exploitation. The public Chromium bug reference may not provide enough detail for independent exploitability assessment.

Researcher notes

The available description is sparse: no CVSS, CWE, or detailed public root-cause data is included. Validation should avoid exploit reproduction and focus on affected version discovery, extension policy review, and advisory-to-package mapping for Chrome or Chromium builds.

Mitigation direction

  • Update Chrome to 90.0.4430.212 or later, preferably the latest stable release.
  • Apply Chromium package updates from applicable Linux distribution advisories.
  • Restrict browser extension installation to approved, managed extensions.
  • Audit installed extensions and remove untrusted or unnecessary entries.
  • Check Google and distribution vendor guidance for any additional remediation details.

Validation and detection

  • Inventory Chrome and Chromium versions across endpoints and servers.
  • Confirm all managed browsers report version 90.0.4430.212 or later.
  • Review extension management policy for allowlisting and user-install restrictions.
  • Sample endpoints for unauthorized or risky installed extensions.
  • Track remediation against Gentoo, Fedora, and Google advisory coverage where applicable.
Prepared
Confidence
medium
Sources
7

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

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CVE-2021-30511 mapping review

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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
6Source 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
GoogleChromeunspecifiedListed
Weakness

CWE details

No CWE listed

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