CVE-2025-38423: Linux Kernel ASoC Codec Driver Double Free Vulnerability
This post details a recently resolved vulnerability, CVE-2025-38423, affecting the Linux kernel's Advanced Linux Sound Architecture (ASoC) subsystem. Specifically, the vulnerability lies within the wcd9375 codec driver and involves a double free condition, which can lead to system instability and potentially, privilege escalation.
Vulnerability Details
- CVE ID: CVE-2025-38423
- Description: The wcd9375 codec driver in the Linux kernel incorrectly manages regulator supplies during error and removal paths. It attempts to free regulator resources twice, leading to a double-free condition.
- CVSS Score: Currently awaiting analysis, likely to be medium to high depending on exploitability.
- CVSS Vector: Awaiting analysis, but likely includes factors for local access and potential for denial of service or limited privilege escalation.
- Exploit Requirements: Exploitation would require local access to the system and the ability to trigger the vulnerable code path within the ASoC subsystem. This often involves interacting with audio devices and drivers.
- Affected Vendor, Product, Version: Linux kernel versions prior to the fix containing the vulnerable wcd9375 codec driver.
- CWE: CWE-415 - Double Free. A double-free condition occurs when memory that has already been freed is freed again. This can corrupt memory management structures, leading to crashes, denial of service, or potentially, arbitrary code execution.
Timeline of Events
- 2025-07-25: CVE-2025-38423 assigned.
- 2025-07-25: Vulnerability details published.
- Fix: Patches available in the kernel stable branches (see references).
Exploitability & Real-World Risk
While a double-free vulnerability can be severe, the exploitability of this specific flaw depends on several factors. The need for local access reduces the immediate risk compared to remotely exploitable vulnerabilities. However, a successful exploit could lead to kernel crashes or, in some scenarios, privilege escalation. The real-world risk is moderate, primarily affecting systems where users frequently interact with audio devices and drivers, increasing the chances of triggering the vulnerable code path.
Recommendations
- Apply Patches: Upgrade to a Linux kernel version containing the fix for this vulnerability. Check with your distribution vendor for specific patch availability.
- Monitor Systems: Keep an eye on system logs for any unusual audio-related errors or crashes.
- Security Best Practices: Adhere to general security best practices, such as minimizing user privileges and regularly updating software.
Technical Insight
The root cause lies in the driver's handling of regulator supplies (power management components). The driver uses devm_regulator_bulk_get() to acquire these supplies. The fix ensures that regulator_bulk_free() is not called in error or removal paths if devm_regulator_bulk_get() was used, preventing the double free.
Credit to Researcher(s)
The vulnerability was identified and fixed by kernel developers during routine code review and maintenance.
References
Tags
#Linux #Kernel #ASoC #Codec #DoubleFree #Security #CVE-2025-38423
Summary: CVE-2025-38423 is a double-free vulnerability in the Linux kernel's wcd9375 codec driver. Incorrect handling of regulator supplies during error conditions can lead to memory corruption and potential system instability. A patch is available to address this issue.
CVE ID: CVE-2025-38423
Risk Analysis: The real-world risk is moderate, primarily affecting systems where users frequently interact with audio devices and drivers, increasing the chances of triggering the vulnerable code path. Could lead to kernel crashes or privilege escalation.
Recommendation: Upgrade to a Linux kernel version containing the fix for this vulnerability. Monitor systems for any unusual audio-related errors or crashes. Adhere to general security best practices.
Timeline
- 2025-07-25: CVE-2025-38423 assigned and vulnerability details published.