# CVE-2021-47012: linux: In the Linux kernel, the following vulnerability has been resolved:  RDMA/siw: Fix a use after free in siw_alloc_mr...

CVE-2021-47012 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47012, released February 28, 2024. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2021-47012
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0027
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Feb 28, 2024

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.10.38-1 | [DEBIAN-CVE-2021-47012](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47012.md) | Feb 28, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.10.38-1 | [DEBIAN-CVE-2021-47012](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47012.md) | Feb 28, 2024 |
| Linux | linux Debian 14 | 5.10.38-1 | [DEBIAN-CVE-2021-47012](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47012.md) | Feb 28, 2024 |

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