CVE-2026-63823

About vulnerability

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

keys: Pin request_key_auth payload in instantiate paths

A: request_key() B: KEYCTL_INSTANTIATE_IOV ================ =========================

create auth key store rka in auth key wait for helper get auth key load rka from auth key copy user payload sleep on #PF

helper completed detach and free rka destroy auth key wake up use rka->target_key USE-AFTER-FREE

Give request_key_auth payloads a refcount. Take a payload reference while authkey->sem stabilizes the payload and revocation state. Hold that reference across the instantiate and reject paths. Drop the auth key owning reference from revoke and destroy.

[jarkko: Replaced the first two paragraphs of text with an actual concurrency scenario.]

Affected product:

AlmaLinux 9.2 ESU , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , RHEL 7 ELS , TuxCare 9.6 ESU

Affected packages:

kernel @ 4.18.0 (+6 more)

Live-patch status from KernelCare for each operating system.