CVE-2024-57876

A race condition was found in the Linux kernel's DisplayPort Multi-Stream Transport (DP MST) subsystem, affecting the kernel and kernel-rt in Red Hat Enterprise Linux 8, 9, and 10. If a DisplayPort MST topology is removed while an MST sideband message (a down reply or an up request) is being received, the message reception state can be reset by one thread via drm_dp_mst_topology_mgr_set_mst(false) while another thread reads and parses the same message without holding a lock. This race can lead to memory corruption and a denial of service through a system crash. Red Hat rated this flaw as Moderate (CVSS 4.6, AV:P/AC:H/PR:L) because triggering it requires physical access to the DisplayPort connector, or local access combined with disconnecting a DisplayPort MST device at the precise moment a sideband message is being processed; this is more restrictive than the NIST score of 7.0, which assumes a broader local attack scope. Red Hat Enterprise Linux 6 and 7 are not affected because the vulnerable code is not present in those products. For the RHEL 8 kernel the fix is deferred due to the limited practical exploitability (physical or local access plus a narrow timing window), leaving a residual risk of a physical or local denial of service. In the remaining affected streams, including the RHEL 9 and RHEL 10 kernels and kernel-rt and the Hosted OpenShift (ARO and OSD) environments, remediation is delegated to the respective engineering teams; fixes have been pursued for the RHEL 9.4.z and RHEL 9.6 kernel streams.