CVE-2021-1782

CWE-667 in A race condition was addressed with improved locking

Verified by Precogs Threat Research
Last Updated: Oct 23, 2025
Base Score
7HIGH

Executive Summary

CVE-2021-1782 is a high severity vulnerability affecting appsec. It is classified as CWE-667. This vulnerability is actively being exploited in the wild.

Precogs AI Insight

"A race condition in the XNU kernel allows a malicious application to elevate privileges to root. Attackers execute concurrent operations to corrupt kernel structures during critical state changes. Precogs Binary Analysis detects missing locking primitives and synchronization errors."

Exploit Probability (EPSS)
Moderate (5.9%)
Public POC
Available
Exploit Probability
Elevated (52%)
Public POC
Actively Exploited
Affected Assets
appsecCWE-667

What is this vulnerability?

CVE-2021-1782 is categorized as a high CWE-667 flaw with a CVSS base score of 7. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

A race condition was addressed with improved locking. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, watchOS 7.3, tvOS 14.4, iOS 14.4 and iPadOS 14.4. A malicious application may be able to elevate privileges. Apple is aware of a report that this issue may have been actively exploited..

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 Score7 (HIGH)
Vector StringCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
PublishedApril 2, 2021
Last ModifiedOctober 23, 2025
Related CWEsCWE-667, CWE-667

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-2021-1782

  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

A race condition in the XNU kernel allows a malicious application to elevate privileges to root. Attackers execute concurrent operations to corrupt kernel structures during critical state changes. Precogs Binary Analysis detects missing locking primitives and synchronization errors.

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

Is your system affected?

Precogs AI detects CVE-2021-1782 in compiled binaries, LLMs, and application layers — even without source code access.