CVE-2026-89742 — rapidio: mport_cdev: fix use-after-free in dma_req_free()
In the Linux kernel, the following vulnerability has been resolved: rapidio: mport_cdev: fix use-after-free in dma_req_free() dma_req_free() acquires buf_mutex through req->ma…
Published: 2026-09-11 · CVSS: 7.8 · CVSS 3.1
In the Linux kernel, the following vulnerability has been resolved: rapidio: mport_cdev: fix use-after-free in dma_req_free() dma_req_free() acquires buf_mutex through req->map, drops the mapping reference with kref_put(), and then dereferences req->map again to unlock the mutex. If kref_put() drops the last reference, mport_release_mapping() frees the mapping, and the subsequent mutex_unlock() dereferences a freed object. This is a use-after-free. Fix this by caching map and md before kref_put(), clearing req->map while holding buf_mutex, and using the cached md for mutex unlocking. The bug is reachable from userspace via the RapidIO mport character device interface.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7