Threats / Google / CVE-2021-30551
CVE-2021-30551
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Google Chromium V8 vulnerability
Type confusion vulnerability in Google Chromium V8 engine allows remote attackers to exploit heap corruption through crafted HTML pages, affecting multiple browsers including Chrome, Edge, and Opera.
Verdict
Today item — known-exploited.
A type confusion flaw in V8 enables remote code execution via malicious web content. The high EPSS score and active exploitation indicate immediate risk to browser users. Patch deployment is critical.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit 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
6 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).
Probability (EPSS)
EPSS 0.64701 — 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.
Weakness (CWE)
Mapped to CWE-122 Heap-based Buffer Overflow, CWE-843 Type Confusion — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution 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 board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious HTML page that triggers type confusion in the V8 JavaScript engine.
Business
Users visiting untrusted websites face arbitrary code execution within browser context.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit heap corruption to gain memory control and execute shellcode with browser privileges.
Business
Attackers can steal credentials, install malware, or pivot to system compromise affecting enterprise endpoints.
3
Lateral reach — past segmentation narrative 3
Attacker
I distribute the exploit through compromised ad networks or watering hole attacks targeting specific user groups.
Business
Organizations experience data breaches, credential theft, and potential lateral movement into internal networks.
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