CVE-2026-64484 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
ALSA: es1938: check snd_ctl_new1() return value
snd_ctl_new1() can return NULL when memory allocation fails. snd_es1938_mixer() does not check the return value before dereferencing the pointer, which can lead to a NULL pointer dereference.
Add a NULL check after snd_ctl_new1() and return -ENOMEM if it fails.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/25/2026
The vulnerability in question affects the Linux kernel's ALSA (Advanced Linux Sound Architecture) subsystem, specifically within the es1938 driver that manages ESS Technology ES1938 sound chips. This issue represents a classic null pointer dereference vulnerability that can lead to system instability and potential denial of service conditions. The es1938 driver is responsible for handling audio input/output operations on hardware devices manufactured by ESS Technology, making it an integral component of the kernel's sound management infrastructure.
The technical flaw stems from improper error handling in the snd_es1938_mixer() function where the return value of snd_ctl_new1() is not validated before subsequent operations. The snd_ctl_new1() function serves as a critical memory allocation routine that creates new control elements for the ALSA subsystem, and like many kernel memory allocation functions, it can legitimately return NULL when the system encounters memory exhaustion conditions. However, the es1938 driver implementation fails to account for this possibility, directly proceeding to dereference the potentially null pointer without verification.
This type of vulnerability falls under CWE-476 which specifically addresses NULL Pointer Dereference in software systems. The operational impact of this flaw is significant as it can cause the kernel to crash when attempting to initialize or configure sound controls on ES1938 hardware, resulting in complete system instability during audio operations. The vulnerability is particularly concerning because it occurs during driver initialization, meaning that any system utilizing ES1938 sound hardware could experience unexpected termination of audio subsystem functionality, potentially requiring system reboot to restore normal operation.
The mitigation strategy involves implementing proper error handling by adding a NULL check immediately after the snd_ctl_new1() call as specified in the resolution. This approach aligns with established kernel development practices and security guidelines that mandate thorough validation of all memory allocation operations. When snd_ctl_new1() returns NULL, the driver should properly handle this condition by returning -ENOMEM to indicate insufficient memory resources rather than proceeding with undefined behavior. This fix directly addresses the ATT&CK technique T1499.004 which involves system resource exhaustion attacks and ensures that kernel subsystems maintain robust error handling even under memory pressure conditions.
The vulnerability demonstrates how seemingly minor oversight in error checking can create significant security implications within kernel space operations. Proper validation of allocation functions is essential for maintaining system stability, as memory allocation failures are not exceptional circumstances but rather common occurrences that must be gracefully handled to prevent system crashes and maintain overall system reliability. This fix exemplifies the importance of defensive programming practices in kernel development where every potential failure point must be explicitly considered and handled according to established error propagation conventions within the Linux kernel ecosystem.