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Threats / Google / CVE-2021-38000
CVE-2021-38000 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Google Chromium Intents vulnerability

Chromium Intents improperly validates input, allowing remote attackers to redirect browsers to malicious URLs via crafted HTML pages.

Verdict

Today item — known-exploited.

A remote attacker can craft HTML to exploit improper input validation in Chromium Intents, causing arbitrary browser navigation to attacker-controlled URLs. This affects multiple Chromium-based browsers and has been exploited in the wild.

CISA KEV Yes · 2021-11-033EPSS 0.04485 (verify live)4
01

Is it exploitable?

— the evidence, ranked above the score
Reported exploitation
4 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 0.04485 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Google, Chromium Intents. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.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 a specially formed intent that bypasses input validation.
Business
Users are exposed to phishing, malware distribution, or credential harvesting through forced navigation to attacker-controlled sites.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I host the HTML page and distribute it via email, social engineering, or compromised websites to reach target users.
Business
Attack surface expands across multiple Chromium-based browsers, increasing organizational risk and potential for widespread compromise.
3

Lateral reach — past segmentation narrative 3

Attacker
I redirect victims to landing pages that harvest credentials, deliver malware, or perform drive-by downloads.
Business
Compromised user accounts, infected endpoints, and data exfiltration result in operational disruption and potential regulatory exposure.
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)
  • 4 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • 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.