Threats / Google / CVE-2021-38000
CVE-2021-38000
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
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 · 2021-11-034EPSS 0.04485 (verify live)5CVSS 6.1 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: partial3
01
Is it exploitable?
— the evidence, ranked above the scoreReported 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).
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
CVSS 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N) · Affected: Google, Chromium Intents. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: partialCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog the same day the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
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 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