CVE-2025-38421: Double Free Vulnerability in Linux Kernel AMD PMF Driver
A critical vulnerability has been identified in the Linux kernel's AMD PMF (Platform Management Framework) driver. This flaw, tracked as CVE-2025-38421, could lead to a double-free scenario, potentially causing system instability or a denial-of-service.
Vulnerability Details
- CVE ID: CVE-2025-38421
- Description: A double-free vulnerability exists in the AMD PMF driver within the Linux kernel. If the setup of smart PC fails, the memory allocated to
dev->bufmay be freed twice during the unloading of the amd-pmf module, resulting in system instability or a denial-of-service. - CVSS Score and Vector: Due to the 'Awaiting Analysis' status, CVSS information is unavailable. However, memory corruption vulnerabilities like double-frees can often lead to escalating privileges or denial of service. Expect at least a 6.0 (Medium) score when details become available.
- Exploit Requirements: Exploiting this vulnerability would likely require local access or the ability to trigger specific error conditions within the AMD PMF driver.
- Affected Vendor, Product, Version: Linux kernel (versions prior to the fix) on systems utilizing the AMD PMF driver. Specific vulnerable versions depend on when the fix was incorporated into different kernel branches.
- CWE: CWE-415 - Double Free. A double-free vulnerability occurs when the same memory location is freed twice. This can corrupt the memory management structures, leading to unpredictable behavior, including crashes or potential security exploits.
Timeline of Events
- 2025-07-25: Vulnerability disclosed and assigned CVE-2025-38421.
- [Date of Fix]: Patch committed to the Linux kernel. See references for specific commit details.
Exploitability & Real-World Risk
While exploitation may require specific conditions to be met, the potential consequences of a double-free vulnerability are severe. An attacker could potentially leverage this flaw to crash the system or, in more sophisticated scenarios, gain unauthorized access. The risk is higher for systems where untrusted processes can interact with the AMD PMF driver.
Recommendations
- Apply Kernel Patches: Update your Linux kernel to the latest stable version that includes the fix for this vulnerability. Consult your distribution's security advisories for specific patching instructions.
- Monitor System Logs: Regularly monitor system logs for any unusual behavior or errors related to the AMD PMF driver.
- Follow Security Best Practices: Employ general security best practices, such as keeping your system software up to date and limiting access to sensitive resources.
Technical Insight
The vulnerability arises because the dev->buf buffer within the AMD PMF driver might be freed during an error condition but not set to NULL. Subsequently, the amd_pmf_remove() function attempts to free the same memory again, resulting in the double free. The patch addresses this by ensuring device-managed allocations are used to prevent such double-free scenarios.
Credit to Researcher(s)
The specific researcher or organization that discovered this vulnerability is currently not available.
References
Tags
#Linux #Kernel #AMD #DoubleFree #CVE-2025-38421 #Security
Summary: A double-free vulnerability exists in the Linux kernel's AMD PMF driver (CVE-2025-38421). If smart PC setup fails, memory may be freed twice, leading to system instability. Update your kernel to the latest patched version to mitigate this risk.
CVE ID: CVE-2025-38421
Risk Analysis: Successful exploitation could lead to system instability, denial of service, or potentially unauthorized access.
Recommendation: Update your Linux kernel to the latest stable version that includes the fix for this vulnerability. Consult your distribution's security advisories for specific patching instructions.
Timeline
- 2025-07-25: Vulnerability disclosed and assigned CVE-2025-38421.