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Threats / Google / CVE-2021-30632
CVE-2021-30632 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Google Chromium V8 vulnerability

Out-of-bounds write vulnerability in Chromium V8 engine allows remote attackers to corrupt heap memory via crafted HTML, affecting multiple browsers including Chrome, Edge, and Opera.

Verdict

Today item — known-exploited.

Remote code execution risk through heap corruption. Attackers can exploit this via malicious web pages to potentially achieve arbitrary code execution in the context of affected browsers. Active exploitation in the wild increases urgency.

CISA KEV Yes · 2021-11-033EPSS 0.64546 (verify live)4Exploit Public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
3 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.64546 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Google, Chromium V8. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-122 Heap-based Buffer Overflow — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution not established

No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I craft a malicious HTML page containing specially designed JavaScript that triggers the out-of-bounds write in V8.
Business
Users visiting attacker-controlled or compromised websites face immediate risk of browser compromise and potential system-level code execution.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I host this page on a website or inject it into legitimate sites through advertising networks or watering hole attacks.
Business
Attack surface expands across the web; users cannot easily distinguish malicious content from legitimate browsing.
3

Lateral reach — past segmentation narrative 3

Attacker
I exploit heap corruption to achieve arbitrary code execution within the browser process.
Business
Confidential data accessible to the browser, including credentials, session tokens, and personal information, becomes compromised.
4

Data at risk — exfiltration narrative 4

Attacker
I leverage browser execution context to install malware, establish persistence, or pivot to the underlying operating system.
Business
Enterprise and consumer endpoints face full compromise; incident response and remediation costs escalate significantly.
04

What to do

— defensible action
  • Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 3 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • Public exploit availability
  • Catalogued by Chrome (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by ChromeCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.