CVE-2025-9408
📋 TL;DR
A race condition in system call entry on Cortex-M processors allows malicious userspace processes to escalate privileges and execute arbitrary code with kernel privileges. This affects embedded systems running Zephyr RTOS on ARM Cortex-M chips. Attackers with local access can exploit this to gain full system control.
💻 Affected Systems
- Zephyr RTOS
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary code with kernel privileges, bypass all security controls, and potentially achieve persistence.
Likely Case
Privilege escalation from userspace to kernel mode, enabling unauthorized access to sensitive resources and system manipulation.
If Mitigated
Limited impact if systems have strict access controls, minimal attack surface, and no untrusted userspace processes.
🎯 Exploit Status
Exploitation requires local access and knowledge of the race condition timing. The advisory includes technical details that could facilitate exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Zephyr security advisory for specific patched versions
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-3r6j-5mp3-75wr
Restart Required: Yes
Instructions:
1. Review the Zephyr security advisory. 2. Update to the latest patched version of Zephyr RTOS. 3. Rebuild and redeploy firmware to affected devices. 4. Verify the fix is applied.
🔧 Temporary Workarounds
Disable unnecessary system calls
allReduce attack surface by disabling non-essential system calls in kernel configuration
Modify Kconfig to disable CONFIG_USERSPACE for non-essential features
Implement process isolation
allUse Zephyr's memory protection features to isolate untrusted processes
Configure memory domains and partitions in device tree
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Deploy network segmentation to isolate vulnerable devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and build configuration. Systems with CONFIG_USERSPACE enabled on Cortex-M are vulnerable.Check Version:
Check Zephyr version in build configuration or use device firmware identification toolsVerify Fix Applied:
Verify Zephyr version is updated to patched release and rebuild firmware with updated source.📡 Detection & Monitoring
Log Indicators:
- Unexpected privilege escalation events
- Kernel mode operations from userspace processes
- System call anomalies
Network Indicators:
- Unusual device behavior or communications post-exploitation
SIEM Query:
Search for privilege escalation events or unauthorized kernel access in system logs