CVE-2019-5521

What is this vulnerability?

CVE-2019-5521 is categorized as a critical Out-of-bounds Read 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.

VMware ESXi (6.7 before ESXi670-201904101-SG and 6.5 before ESXi650-201903001), Workstation (15.x before 15.0.3 and 14.x before 14.1.6) and Fusion (11.x before 11.0.3 and 10.x before 10.1.6) contain an out-of-bounds read vulnerability in the pixel shader functionality. Successful exploitation of this issue may lead to information disclosure or may allow attackers with normal user privileges to create a denial-of-service condition on the host. Exploitation of this issue require an attacker to have access to a virtual machine with 3D graphics enabled. It is not enabled by default on ESXi and is enabled by default on Workstation and Fusion.

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-2019-5521

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

Precogs Binary SAST/DAST engine performs deep structural analysis of compiled binaries, detecting memory corruption, control-flow hijacking, and privilege escalation vulnerabilities without requiring source code access.

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: Out-of-bounds read
void read_data(char *input, int length) {
    char buffer[64] = {0};
    // Taint sink: reads beyond buffer size if length > 64
    memcpy(buffer, input, length);
}

Secure Code Pattern

// ✅ SECURE: Bounded read
void read_data(char *input, int length) {
    char buffer[64] = {0};
    // Sanitized boundary check
    int safe_length = (length > sizeof(buffer)) ? sizeof(buffer) : length;
    memcpy(buffer, input, safe_length);
}

How Precogs Detects This

Precogs Binary SAST engine explicitly uncovers memory boundary violations and unsafe memory management functions in compiled binaries.