CVE-2021-28663

What is this vulnerability?

CVE-2021-28663 is categorized as a high Use After Free 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.

The Arm Mali GPU kernel driver allows privilege escalation or information disclosure because GPU memory operations are mishandled, leading to a use-after-free. This affects Bifrost r0p0 through r28p0 before r29p0, Valhall r19p0 through r28p0 before r29p0, and Midgard r4p0 through r30p0.

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-2021-28663

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 use-after-free vulnerability in the Arm Mali GPU driver allows memory corruption. Attackers leverage GPU memory mismanagement to escalate privileges or extract sensitive memory contents. Precogs Binary SAST intercepts dangling pointers within kernel-mode drivers.

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.

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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