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.
History

Wed, 24 Jun 2026 17:15:00 +0000

Type Values Removed Values Added
Description 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.
Title greybus: raw: fix use-after-free on cdev close
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-06-24T16:29:33.971Z

Reserved: 2026-06-09T07:44:35.379Z

Link: CVE-2026-53025

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.