CVE-2025-66627
📋 TL;DR
CVE-2025-66627 is a use-after-free vulnerability in Wasmi's linear memory implementation that occurs under specific memory growth conditions. This allows attackers to potentially corrupt memory, disclose information, or execute arbitrary code. Affected systems include those running vulnerable versions of Wasmi WebAssembly interpreter in constrained or embedded environments.
💻 Affected Systems
- Wasmi WebAssembly interpreter
📦 What is this software?
Wasmi by Wasmi Labs
Wasmi by Wasmi Labs
Wasmi by Wasmi Labs
Wasmi by Wasmi Labs
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, or service disruption
Likely Case
Memory corruption leading to application crashes, denial of service, or limited information disclosure
If Mitigated
Controlled crashes or performance degradation with proper memory isolation and sandboxing
🎯 Exploit Status
Exploitation requires crafting malicious WebAssembly modules that trigger specific memory growth conditions
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.41.2, 0.47.1, 0.51.3, 1.0.1
Vendor Advisory: https://github.com/wasmi-labs/wasmi/security/advisories/GHSA-g4v2-cjqp-rfmq
Restart Required: Yes
Instructions:
1. Identify current Wasmi version. 2. Update to patched version (0.41.2, 0.47.1, 0.51.3, or 1.0.1). 3. Restart affected services. 4. Recompile applications if statically linked.
🔧 Temporary Workarounds
Limit maximum linear memory sizes
allRestrict WebAssembly module memory allocation to reduce attack surface
Configure Wasmi runtime to enforce memory limits via environment or configuration
🧯 If You Can't Patch
- Implement strict WebAssembly module validation and sandboxing
- Deploy network segmentation and restrict access to Wasmi services
🔍 How to Verify
Check if Vulnerable:
Check Wasmi version against affected versions listCheck Version:
wasmi --version or check package managerVerify Fix Applied:
Confirm version is 0.41.2, 0.47.1, 0.51.3, or 1.0.1📡 Detection & Monitoring
Log Indicators:
- Unexpected memory allocation patterns
- Application crashes with memory errors
- Unusual WebAssembly module execution
Network Indicators:
- Suspicious WebAssembly module uploads
- Unusual traffic to Wasmi endpoints
SIEM Query:
source="wasmi" AND (event="memory_error" OR event="crash")