CVE-2026-53025
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk3th percentile — higher than 3% of all known CVEs
Summary
A use-after-free vulnerability was found in the Linux kernel's greybus raw driver. When a raw bundle is disconnected but its character device (cdev) is still open by an application, releasing the cdev accesses freed memory, potentially causing a system crash.
Risk Assessment
The risk involves a refcount underflow and potential kernel panic when an application closes the character device after the device is disconnected. This could lead to service disruption or data loss.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit addressing the issue). Monitor for the patch availability and apply it during the next maintenance window.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: greybus: raw: fix use-after-free on cdev close This addresses a use-after-free bug when a raw bundle is disconnected but its chardev is still opened by an application. When the application releases the cdev, it causes the following panic when init on free is enabled (CONFIG_INIT_ON_FREE_DEFAULT_ON=y): refcount_t: underflow; use-after-free. WARNING: CPU: 0 PID: 139 at lib/refcount.c:28 refcount_warn_saturate+0xd0/0x130 ... Call Trace: <TASK> cdev_put+0x18/0x30 __fput+0x255/0x2a0 __x64_sys_close+0x3d/0x80 do_syscall_64+0xa4/0x290 entry_SYSCALL_64_after_hwframe+0x77/0x7f The cdev is contained in the "gb_raw" structure, which is freed in the disconnect operation. When the cdev is released at a later time, cdev_put gets an address that points to freed memory. To fix this use-after-free, convert the struct device from a pointer to being embedded, that makes the lifetime of the cdev and of this device the same. Then, use cdev_device_add, which guarantees that the device won't be released until all references to the cdev have been released. Finally, delegate the freeing of the structure to the device release function, instead of freeing immediately in the disconnect callback.