CVE-2021-47012: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.3% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: RDMA/siw: Fix a use after free in siw_alloc_mr Our code analyzer reported a UAF. In siw_alloc_mr(), it calls siw_mr_add_mem(mr,..). In the implementation of siw_mr_add_mem(), mem is assigned to mr->mem and then mem is freed via kfree(mem) if xa_alloc_cyclic() failed. Here, mr->mem still point to a freed object. After, the execution continue up to the err_out branch of siw_alloc_mr, and the freed mr->mem is used in siw_mr_drop_mem(mr). My patch moves "mr->mem = mem" behind the if (xa_alloc_cyclic(..)<0) {} section, to avoid the uaf.

Affected products

• Linux Linux Kernel: from 5.3, before 5.4.119 (fixed in 5.4.119); from 5.5, before 5.10.37 (fixed in 5.10.37); from 5.11, before 5.11.21 (fixed in 5.11.21); from 5.12, before 5.12.4 (fixed in 5.12.4)

Published 2024-02-28. Last modified 2026-08-04.