CVE-2026-68438

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description An issue exists in the smp call function single() function when CSD lock debugging is enabled. The csd lock() function uses a non-atomic read-modify-write operation to set the CSD FLAG LOCK bit, allowing multiple CPUs to concurrently prepare the same destination CPU CSD. This can lead to a scenario where two senders overwrite callback fields and enqueue the same llist node, potentially causing the node->next pointer to point to itself. Consequently, the target CPU may become stuck while processing the call single queue, which can cause subsequent synchronous work, such as a TLB shootdown (a mechanism to maintain consistency of translation lookaside buffers across CPUs), to remain queued and trigger soft-lockup warnings or system panics.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.