CVE-2016-5142
Use After Free in The Web Cryptography API (aka WebCrypto) implementation in Blink, as used in Google Chrome before 52
Executive Summary
CVE-2016-5142 is a critical severity vulnerability affecting binary-analysis. It is classified as Use After Free. Ensure your systems and dependencies are patched immediately to mitigate exposure risks.
Precogs AI Insight
"The Web Cryptography API in Google Chrome contains a use-after-free vulnerability. Attackers write malicious JavaScript that calls WebCrypto functions asynchronously, freeing memory while it is still in use to achieve code execution. Precogs Binary SAST natively uncovers complex memory boundary violations."
What is this vulnerability?
CVE-2016-5142 is categorized as a critical Use After Free flaw with a CVSS base score of 9.8. Based on our vulnerability intelligence, this issue occurs when the application fails to securely handle untrusted data boundaries.
The Web Cryptography API (aka WebCrypto) implementation in Blink, as used in Google Chrome before 52.0.2743.116, does not properly copy data buffers, which allows remote attackers to cause a denial of service (use-after-free) or possibly have unspecified other impact via crafted JavaScript code, related to NormalizeAlgorithm.cpp and SubtleCrypto.cpp.
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
| Metric | Value |
|---|---|
| CVSS Base Score | 9.8 (CRITICAL) |
| Vector String | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| Published | August 7, 2016 |
| Last Modified | April 12, 2025 |
| Related CWEs | CWE-416 |
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-2016-5142
- Apply Vendor Patches: Upgrade affected components to their latest, non-vulnerable versions immediately.
- Implement Input Validation: Ensure all user-supplied data is validated, sanitized, and type-checked before processing.
- Deploy Runtime Protection: Use Precogs continuous monitoring to detect exploitation attempts in real time.
- Audit Dependencies: Review and update all third-party libraries and transitive dependencies.
Defending with Precogs AI
The Web Cryptography API in Google Chrome contains a use-after-free vulnerability. Attackers write malicious JavaScript that calls WebCrypto functions asynchronously, freeing memory while it is still in use to achieve code execution. Precogs Binary SAST natively uncovers complex memory boundary violations.
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.
Vulnerability Code Signature
Attack Data Flow
| Stage | Detail |
|---|---|
| Source | Memory allocation pointer |
| Vector | Pointer is accessed after the memory has been freed |
| Sink | Dangling pointer dereference |
| Impact | Memory corruption, sandbox escape, Remote Code Execution (RCE) |
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