CVE-2022-49651

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

srcu: Tighten cleanup_srcu_struct() GP checks

Currently, cleanup_srcu_struct() checks for a grace period in progress, but it does not check for a grace period that has not yet started but which might start at any time. Such a situation could result in a use-after-free bug, so this commit adds a check for a grace period that is needed but not yet started to cleanup_srcu_struct().

This vulnerability is rated as having a Moderate impact because exploitation requires local access and primarily results in a denial of service via a kernel crash rather than arbitrary privilege escalation. The issue stems from inadequate synchronization handling within the kernel Sleepable Read-Copy Update (SRCU) subsystem, where tearing down an SRCU structure before a required grace period commences can cause memory corruption. Because SRCU is an internal kernel synchronization mechanism, triggering this condition requires specific kernel subsystem operations, which limits attacker reachability on default Red Hat Enterprise Linux deployments.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.