CVE-2026-99225

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

keys: Check the authorization payload in process keyring searches

An authorization payload and its saved credentials must remain valid while search process keyrings rcu() searches the requestor's keyrings. The function validates the authorization key, then separately loads payload.data[0] and unconditionally reads rka->cred. Validation does not prevent request key auth revoke() from clearing the payload.

A request-key helper can assume authority and fork a descendant that inherits the authorization key. If the descendant misses in its own keyrings, it falls back to the saved requestor credentials. Successful target instantiation invalidates the authorization key without clearing the payload. After the helper exits, UMH WAIT PROC returns to the requester, which calls complete request key() and revokes that key.

With the descendant paused after validation, the paths can interleave as follows:

This NULL dereference can oops the kernel. RCU delays payload disposal but does not prevent the pointer from being cleared.

Load the payload with dereference key rcu() and require a non-NULL result before validating the authorization key and searching its saved credentials. A non-NULL payload and its credentials remain alive for the caller's RCU read-side section; a cleared payload skips the fallback search and follows the existing error selection.

KASAN report as below:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] RIP: 0010:search process keyrings rcu+0x32b/0x790