CVE-2021-38000

Open Redirect in Insufficient validation of untrusted input in Intents in Google Chrome on Android prior to 95

Verified by Precogs Threat Research
Last Updated: Oct 24, 2025
Base Score
6.1MEDIUM

Executive Summary

CVE-2021-38000 is a medium severity vulnerability affecting appsec. It is classified as Open Redirect. This vulnerability is actively being exploited in the wild.

Precogs AI Insight

"Insufficient validation of Intents in Google Chrome on Android allows unauthorized applications to access browser capabilities. Attackers leverage malicious Android apps to bypass the browser sandbox and execute intents. Precogs Application Security Module maps untrusted inter-process communication boundaries directly to sensitive intent sinks."

Exploit Probability (EPSS)
Low (4.5%)
Public POC
Available
Exploit Probability
Low (<10%)
Public POC
Actively Exploited
Affected Assets
appsecCWE-601

What is this vulnerability?

CVE-2021-38000 is categorized as a medium Open Redirect flaw with a CVSS base score of 6.1. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Insufficient validation of untrusted input in Intents in Google Chrome on Android prior to 95.0.4638.69 allowed a remote attacker to arbitrarily browser to a malicious URL via a crafted HTML page.

This architectural defect enables adversaries to bypass intended security controls, directly manipulating the application's execution state or data layer. Immediate strategic intervention is required.

Risk Assessment

MetricValue
CVSS Base Score6.1 (MEDIUM)
Vector StringCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
PublishedNovember 23, 2021
Last ModifiedOctober 24, 2025
Related CWEsCWE-601, CWE-20, CWE-601

Impact on Systems

Data Exfiltration: Attackers can extract sensitive data from backend databases, configuration files, or internal services.

Authentication Bypass: Exploiting this flaw may allow unauthorized access to protected resources and administrative interfaces.

Lateral Movement: Once initial access is gained, attackers can pivot to internal systems and escalate privileges.

How to Fix and Mitigate CVE-2021-38000

  1. Apply Vendor Patches Immediately: This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog. Apply updates per vendor instructions.
  2. Verify Patch Deployment: Confirm all instances are updated using Precogs continuous monitoring.
  3. Review Audit Logs: Investigate historical access logs for indicators of compromise related to this attack surface.
  4. Implement Defense-in-Depth: Deploy WAF rules, network segmentation, and endpoint detection to limit blast radius.

Defending with Precogs AI

Insufficient validation of Intents in Google Chrome on Android allows unauthorized applications to access browser capabilities. Attackers leverage malicious Android apps to bypass the browser sandbox and execute intents. Precogs Application Security Module maps untrusted inter-process communication boundaries directly to sensitive intent sinks.

Use Precogs to continuously scan your codebase, binaries, APIs, and infrastructure for this vulnerability class and related attack patterns. Our AI-powered detection engine combines static analysis with threat intelligence to identify exploitable weaknesses before attackers do.

Start scanning with Precogs →

Vulnerability Code Signature

Attack Data Flow

StageDetail
SourceUntrusted User Input
VectorInput flows through the application logic without sanitization
SinkExecution or Rendering Sink
ImpactApplication compromise, Logic Bypass, Data Exfiltration

Vulnerable Code Pattern

# ❌ VULNERABLE: Unsanitized Input Flow
def process_request(request):
    user_input = request.GET.get('data')
    # Taint sink: processing untrusted data
    execute_logic(user_input)
    return {"status": "success"}

Secure Code Pattern

# ✅ SECURE: Input Validation & Sanitization
def process_request(request):
    user_input = request.GET.get('data')
    
    # Sanitized boundary check
    if not is_valid_format(user_input):
        raise ValueError("Invalid input format")
        
    sanitized_data = sanitize(user_input)
    execute_logic(sanitized_data)
    return {"status": "success"}

How Precogs Detects This

Precogs AI Analysis Engine maps untrusted input directly to execution sinks to catch complex application security vulnerabilities.\n

Related Vulnerabilitiesvia CWE-601

Is your system affected?

Precogs AI detects CVE-2021-38000 in compiled binaries, LLMs, and application layers — even without source code access.