CVE-2025-0647
📋 TL;DR
This CVE describes a CPU-level vulnerability in certain Arm processors where a specific instruction (CPP RCTX) can prevent proper TLB invalidation, causing the processor to retain stale translation lookaside buffer entries. This affects systems using vulnerable Arm CPUs, potentially allowing privilege escalation or information disclosure across security boundaries. The vulnerability impacts hardware rather than software, making it particularly challenging to address.
💻 Affected Systems
- Arm CPUs with specific microarchitecture implementations
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An attacker could exploit stale TLB entries to bypass memory isolation, potentially gaining unauthorized access to sensitive data or escalating privileges across security domains, including hypervisor escapes in virtualized environments.
Likely Case
Information disclosure where an attacker could access memory regions they shouldn't have access to, potentially leaking sensitive data or cryptographic keys from other processes or virtual machines.
If Mitigated
With proper security controls like strict process isolation, memory protection mechanisms, and limited attack surface, the impact could be reduced to minimal information leakage rather than full privilege escalation.
🎯 Exploit Status
Exploitation requires local access and deep knowledge of CPU microarchitecture. The vulnerability involves precise timing of specific CPU instructions and TLB operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Microcode/firmware updates from CPU vendors
Vendor Advisory: https://developer.arm.com/documentation/111546
Restart Required: Yes
Instructions:
1. Check with your hardware vendor for microcode/firmware updates. 2. Apply the firmware update following vendor instructions. 3. Reboot the system to load the updated microcode. 4. Verify the update was applied successfully.
🔧 Temporary Workarounds
Disable vulnerable CPU features
linuxDisable specific CPU features that use the vulnerable instruction sequence if supported by the OS
echo 0 > /sys/devices/system/cpu/vulnerabilities/cve-2025-0647
🧯 If You Can't Patch
- Implement strict process isolation and memory protection boundaries
- Limit access to systems with vulnerable CPUs to trusted users only
🔍 How to Verify
Check if Vulnerable:
Check CPU microcode version and compare against vendor patched versions. Use 'cat /proc/cpuinfo' and check microcode version.Check Version:
grep -i microcode /proc/cpuinfo | head -1Verify Fix Applied:
Verify microcode version after update matches vendor's patched version. Check system logs for successful microcode loading.📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing microcode updates
- System logs indicating TLB flush anomalies
Network Indicators:
- No network indicators as this is a local CPU vulnerability
SIEM Query:
No specific SIEM query as this is hardware-level and doesn't generate typical application logs