PT-2026-51919 · Linux · Linux

Publicado 2026-06-24 · Atualizado 2026-06-24 · CVE-2026-53025

Mitre

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.

Identificadores relacionados

CVE-2026-53025

Produtos afetados

Linux

Referências · 3

• https://git.kernel.org/stable/c/983cc2c7efbce04ecbf6328448d895044dd6ab31 · Nota
• https://git.kernel.org/stable/c/ef2d97c15b19b3489de01695bce478601e236c3e · Nota
• https://nvd.nist.gov/vuln/detail/CVE-2026-53025 · Nota de Segurança