CVE-2021-30663

What is this vulnerability?

CVE-2021-30663 is categorized as a high Integer Overflow flaw with a CVSS base score of 8.8. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.

An integer overflow was addressed with improved input validation. This issue is fixed in iOS 14.5.1 and iPadOS 14.5.1, tvOS 14.6, iOS 12.5.3, Safari 14.1.1, macOS Big Sur 11.3.1. Processing maliciously crafted web content may lead to arbitrary code execution.

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-2021-30663

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

An integer overflow in the WebKit framework leads to memory corruption and arbitrary code execution. Attackers trick victims into processing crafted web elements that trigger arithmetic overflows. Precogs Binary Analysis identifies hazardous arithmetic operations prior to memory allocations.

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: Integer Overflow
void allocate_memory(unsigned int num_elements) {
    // Taint sink: multiplication may overflow, resulting in a small allocation
    unsigned int size = num_elements * sizeof(int);
    int *array = (int *)malloc(size);
}

Secure Code Pattern

// ✅ SECURE: Safe arithmetic
void allocate_memory(unsigned int num_elements) {
    if (num_elements > UINT_MAX / sizeof(int)) {
        // Handle overflow error
        return;
    }
    unsigned int size = num_elements * sizeof(int);
    int *array = (int *)malloc(size);
}

How Precogs Detects This

Precogs Binary SAST engine identifies unsafe arithmetic operations and integer overflows that lead to memory corruption.\n