rapidio: mport_cdev: fix use-after-free in dma_req_free()

Summary

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.

Timeline

1. Sep 11, 2026, 7:46 PM UTCCVE published
2. Oct 19, 2026, 8:51 AM UTCRecord last updated

Affected versions

• Linux Linux

  From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in 00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6a; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in fc79c07cdcde02c5b17633d78777de6ac2c14b29; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in 26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in bd8881c24a9520f9c3d3e855d866197f63e471a7; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in 9a9929ec875ff20922c90c96fd544ae8a2a61a8d; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in 211c68d817a3d9dc14c0026a59da7cac30f8147e; From e8de370188d098bb49483c287b44925957c3c9b6 · fixed in 5cbef379a94b161726c5f504598bf4791d45cedc

• Linux Linux

  4.6

• KernelLinux

  From 4.6.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8