CVE-2025-39755 in Linux
Summary
by MITRE • 04/18/2025
In the Linux kernel, the following vulnerability has been resolved:
staging: gpib: Fix cb7210 pcmcia Oops
The pcmcia_driver struct was still only using the old .name initialization in the drv field. This led to a NULL pointer deref Oops in strcmp called from pcmcia_register_driver.
Initialize the pcmcia_driver struct name field.
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Analysis
by VulDB Data Team • 02/16/2026
The vulnerability CVE-2025-39755 represents a critical null pointer dereference issue within the Linux kernel's PCMCIA subsystem, specifically affecting the gpib staging driver component. This flaw exists in the staging directory of the kernel source tree, indicating it is part of a driver that has not yet been fully integrated into the mainline kernel but remains available for use. The vulnerability manifests when the cb7210 PCMCIA driver attempts to register itself with the PCMCIA subsystem, creating a condition where the driver's name field remains uninitialized. The issue stems from the pcmcia_driver structure definition where the .name field was not properly initialized during driver setup, causing the kernel to attempt string comparison operations against a null pointer reference.
The technical execution of this vulnerability occurs during the pcmcia_register_driver function call, where the kernel performs a strcmp operation on what should be a valid driver name string but instead encounters a NULL pointer. This specific error pattern falls under CWE-476 which describes NULL Pointer Dereference, and represents a classic case of improper initialization leading to system instability. The PCMCIA subsystem in Linux manages Plug and Play card insertion and removal events, and when this subsystem fails due to such a fundamental initialization error, it can result in kernel oops messages and system crashes. The gpib driver in question handles General Purpose Interface Bus communications, which are critical for scientific and industrial equipment integration, making this vulnerability particularly concerning for systems that rely on such hardware interfaces.
The operational impact of this vulnerability extends beyond simple system crashes to potentially compromise system stability and availability in environments where PCMCIA devices are actively used. When the kernel encounters this null pointer dereference, it triggers an immediate system oops condition that typically results in kernel panic or forced system reboot. This behavior directly impacts the reliability of embedded systems, industrial control systems, and scientific computing environments where gpib interfaces are commonly deployed. The vulnerability affects systems running Linux kernel versions that include the affected staging driver code, particularly those supporting legacy PCMCIA hardware platforms. From an ATT&CK framework perspective, this vulnerability could enable privilege escalation or denial of service conditions, as attackers could potentially exploit the kernel crash to cause system unavailability or potentially manipulate system state during the crash recovery process.
The mitigation strategy for CVE-2025-39755 involves updating to the patched kernel version that properly initializes the name field in the pcmcia_driver structure. System administrators should prioritize kernel updates, particularly in environments where PCMCIA hardware is actively deployed or where system stability is critical. The fix implemented in the kernel patch ensures that the name field within the pcmcia_driver structure is properly populated before the driver registration process begins, eliminating the null pointer dereference condition. Organizations should also conduct vulnerability assessments to identify systems running affected kernel versions and ensure proper testing of kernel updates in production environments. Additionally, monitoring for kernel oops messages related to PCMCIA subsystem failures should be implemented as part of system health monitoring to detect potential exploitation attempts or unpatched systems.