CVE-2023-52483

A use-after-free vulnerability was found in the Linux kernel, which affects the mctp component and is caused by route lookups that traverse the net's route list without the RCU read lock held. This issue can result in a use-after-free situation where the kfree() function is called on a route pointer that is still in use, given the potential for preemption during the route lookup.

A moderate-severity use-after-free flaw was found in the Linux kernel's MCTP (Management Component Transport Protocol) subsystem. MCTP route lookups traversed a network namespace's route list without holding the RCU read-side lock, so preemption during a route lookup could race with route removal and result in kfree() being called on a route pointer that was still in use. Exploitation requires local access to a system on which the MCTP subsystem is configured and used, and the CVSS 3.1 vector (AV:L/AC:L/PR:L) reflects this local, privileged attack path. Red Hat rates the impact of this flaw as MODERATE, while the generic CVSS 3.1 base score of 7.8 represents the worst-case local impact on systems where MCTP is in use.

The affected MCTP source files are not built in the Red Hat Enterprise Linux 8 and 9 kernel and kernel-rt packages, as confirmed by the automated build check recorded on this flaw, so Red Hat Enterprise Linux 8 and 9 and Red Hat's hosted OpenShift offerings (Azure Red Hat OpenShift and OpenShift Dedicated) are not affected. The Fedora community project is affected, and a fix is being pursued through the community kernel update process, with the upstream resolution performing MCTP route lookups under the RCU read-side lock.

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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. Fedora users can obtain the fix by applying the available Fedora kernel updates through the standard Fedora update mechanism.