CVE-2025-29943
📋 TL;DR
A write-what-where condition vulnerability in AMD CPUs allows an administrator-privileged attacker to modify CPU pipeline configuration, potentially corrupting the stack pointer within SEV-SNP guests. This affects systems using AMD processors with SEV-SNP enabled. Only attackers with administrative privileges can exploit this vulnerability.
💻 Affected Systems
- AMD EPYC processors with SEV-SNP
⚠️ 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 compromise of SEV-SNP guest integrity, allowing arbitrary code execution, data corruption, or guest escape from the secure enclave.
Likely Case
Denial of service or data corruption within SEV-SNP guests, potentially disrupting secure workloads and confidential computing operations.
If Mitigated
Limited impact if proper access controls prevent unauthorized administrative access and SEV-SNP is not used for critical workloads.
🎯 Exploit Status
Exploitation requires administrative access and detailed knowledge of CPU internals and SEV-SNP implementation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Microcode updates and AGESA firmware updates as specified in AMD-SB-3027
Vendor Advisory: https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-3027.html
Restart Required: Yes
Instructions:
1. Check AMD advisory for affected processor models. 2. Obtain updated microcode from system vendor. 3. Update system BIOS/UEFI with latest AGESA firmware. 4. Apply microcode updates through operating system mechanisms. 5. Reboot system to activate updates.
🔧 Temporary Workarounds
Disable SEV-SNP
allTemporarily disable SEV-SNP feature if not required for workloads
Check BIOS/UEFI settings for SEV-SNP option and disable
Restrict Administrative Access
allLimit administrative privileges to trusted personnel only
🧯 If You Can't Patch
- Isolate affected systems from untrusted networks and users
- Implement strict access controls and monitoring for administrative activities
🔍 How to Verify
Check if Vulnerable:
Check processor model and microcode version: cat /proc/cpuinfo | grep -E 'model|microcode' and compare with AMD advisoryCheck Version:
cat /proc/cpuinfo | grep -E 'model name|microcode'Verify Fix Applied:
Verify microcode version after update: dmesg | grep -i microcode and ensure version matches patched version from advisory📡 Detection & Monitoring
Log Indicators:
- Unexpected system crashes or reboots
- SEV-SNP guest failures
- Microcode update failures
Network Indicators:
- None - local exploitation only
SIEM Query:
Search for: (event_source="kernel" AND message="SEV-SNP error") OR (event_source="system" AND message="microcode update")