CVE-2021-21142

What is this vulnerability?

CVE-2021-21142 is categorized as a critical Use After Free flaw with a CVSS base score of 9.6. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

Use after free in Payments in Google Chrome on Mac prior to 88.0.4324.146 allowed a remote attacker to potentially perform a sandbox escape 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

Impact on Systems

✅ Remote Code Execution: Attackers can overwrite the instruction pointer to redirect execution to malicious shellcode.

✅ Memory Corruption: Overwriting adjacent memory regions can corrupt critical application state, leading to privilege escalation.

✅ Denial of Service: Triggering segmentation faults results in immediate disruption of critical systems.

How to Fix and Mitigate CVE-2021-21142

1. Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
2. Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
3. Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
4. Audit Dependencies: Review and update all third-party libraries and transitive dependencies.

Defending with Precogs AI

Google Chrome on Mac contains a use-after-free vulnerability in the Payments subsystem. Attackers use crafted JavaScript interacting with the Payment Request API to manipulate freed memory, leading to remote code execution. Precogs Binary SAST uncovers missing boundary validations in complex protocol parsers.

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

Vulnerable Code Pattern

// ❌ VULNERABLE: Use After Free
char *ptr = malloc(256);
free(ptr);
// Taint sink: accessing freed memory
strcpy(ptr, "Exploit payload");

Secure Code Pattern

// ✅ SECURE: Nullifying pointers
char *ptr = malloc(256);
free(ptr);
// Sanitized state: pointer set to NULL
ptr = NULL;

How Precogs Detects This

Precogs Binary SAST engine identifies dangling pointers and complex use-after-free conditions in compiled rendering engines and system libraries.\n