CVE-2026-99224

Status: UPDATED  |  Advisory ID: CVE-2026-99224

Key Details

Affected Products, Subsystems & Sectors

What to Know

In the Linux kernel, the following vulnerability has been resolved:

keys: Protect the type name while describing a key

keyctl_describe_key() must keep the key type's name alive until

kasprintf() has consumed it. The retained key reference keeps the key

and its description alive, but does not pin the module providing its

type. The name is passed to kasprintf() without holding key->sem.

kvasprintf() uses the saved name pointer in two formatting passes, with

a GFP_KERNEL allocation between them. With AF_RXRPC=m, a task that

passes View permission before type retirement can overlap a privileged

module unload in this order:

1. KEYCTL_DESCRIBE looks up the key, saves key->type->name in the

kasprintf() arguments and completes the first formatting pass.

2. While the formatter is delayed before its second pass,

af_rxrpc_exit() calls unregister_key_type(), which removes the type

from the registry and waits for key_gc_keytype().

3. The collector takes key->sem for writing, retypes the retained key

to key_type_dead and completes retirement. Unregistration and module

exit return, allowing free_module() to release the type and name.

4. The formatter resumes its second pass and reads the saved name from

released module storage, which can fault in string().

Hold key->sem for reading across kasprintf(). The collector then cannot

retype the key or complete retirement until both formatting passes have

finished. If retirement wins the lock first, formatting uses the core

key_type_dead name instead. Release the semaphore immediately after

kasprintf(), including on allocation failure, before copying to

userspace.

Oops report as below:

BUG: unable to handle page fault for address: fffffbfff8054794

#PF: supervisor read access in kernel mode

#PF: error_code(0x0000) - not-present page

RIP: 0010:string+0x23f/0x470

Call Trace:

vsnprintf+0x330/0x1110 (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References