CVE-2024-21961 – This vulnerability allows an attacker with acce... (How to Fix)

Q: What is the severity of CVE-2024-21961?

CVE-2024-21961 has a CVSS score of N/A (Unknown). This vulnerability allows an attacker with access to a guest virtual machine to exploit a memory buffer issue in PCIe Link, potentially causing a denial of service attack against the host system. This affects AMD systems with vulnerable PCIe implementations, primarily impacting virtualized environments where guest-to-host attacks are possible.

📋 TL;DR

This vulnerability allows an attacker with access to a guest virtual machine to exploit a memory buffer issue in PCIe Link, potentially causing a denial of service attack against the host system. This affects AMD systems with vulnerable PCIe implementations, primarily impacting virtualized environments where guest-to-host attacks are possible.

💻 Affected Systems

Products:

AMD processors with vulnerable PCIe implementations

Versions: Specific versions not detailed in references; check AMD advisories for exact affected products

Operating Systems: All operating systems running on affected AMD hardware

Default Config Vulnerable: ⚠️ Yes

Notes: Requires virtualization environment with guest VM access; bare metal systems not directly vulnerable unless running hypervisor.

⚠️ 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.

Recommended Actions:

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 host system crash or instability leading to loss of availability for all VMs and services running on the affected host.

🟠

Likely Case

Temporary host instability or performance degradation affecting multiple virtual machines.

🟢

If Mitigated

Minimal impact if proper isolation controls and patches are applied, with potential for performance monitoring alerts only.

🌐 Internet-Facing: LOW - Requires guest VM access, not directly exploitable from internet.

🏢 Internal Only: MEDIUM - Requires compromised guest VM or malicious insider with VM access.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires guest VM access and knowledge of memory manipulation; no public exploits known.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check AMD-SB-3023 and AMD-SB-4013 for specific firmware/BIOS updates

Vendor Advisory: https://www.amd.com/en/resources/product-security/bulletin/AMD-SB-3023.html

Restart Required: Yes

Instructions:

1. Check AMD advisories for affected products. 2. Download appropriate firmware/BIOS updates from AMD. 3. Apply updates following vendor instructions. 4. Reboot affected systems.

🔧 Temporary Workarounds

Isolate Guest VMs

all

Restrict guest VM access and implement strict VM isolation policies

Monitor Host Stability

all

Implement enhanced monitoring for host system crashes or instability

🧯 If You Can't Patch

Implement strict access controls to prevent unauthorized guest VM access
Monitor for unusual host instability and have incident response plans ready

🔍 How to Verify

Check if Vulnerable:

Check system BIOS/firmware version against AMD's affected products list in advisories

Check Version:

On Linux: 'sudo dmidecode -t bios'; On Windows: 'wmic bios get smbiosbiosversion'

Verify Fix Applied:

Verify BIOS/firmware version has been updated to patched version specified by AMD

📡 Detection & Monitoring

Log Indicators:

Unexpected host system crashes
Hypervisor stability alerts
PCIe-related error messages in system logs

Network Indicators:

None - this is a local memory corruption vulnerability

SIEM Query:

Search for: 'system crash' OR 'kernel panic' OR 'hypervisor failure' on virtualization hosts

📊 Metadata

CVE ID: CVE-2024-21961

CVSS v3 Score: N/A (Unknown)

CWE: CWE-119

EPSS Score: 0.01% exploit probability (2th percentile)

Published: February 13, 2026

Last Updated: February 13, 2026

🔗 References

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🔗 Related Vulnerabilities

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