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Review reviewHigh

CVE-2021-47012

Linux Linux, linux kernel

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...

CVSS
7.8
EPSS
0.27%
18.7% percentile
CISA KEV
Not listed
Published
2024.02.28
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.27%
Technical severityCVSS 7.8

Vulnerability overview

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...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 2251334dcac9eb337575d8767e2a6a7e81848f7f < 30b9e92d0b5e5d5dc1101ab856c17009537cbca4, >= 2251334dcac9eb337575d8767e2a6a7e81848f7f < 608a4b90ece039940e9425ee2b39c8beff27e00c, >= 2251334dcac9eb337575d8767e2a6a7e81848f7f < 3e22b88e02c194f6c80867abfef5cc09383461f4, >= 2251334dcac9eb337575d8767e2a6a7e81848f7f < ad9ce7188432650469a6c7625bf479f5ed0b6155, >= 2251334dcac9eb337575d8767e2a6a7e81848f7f < 3093ee182f01689b89e9f8797b321603e5de4f63, >= 5.3, >= 5.3 < 5.4.119, >= 5.5 < 5.10.37, >= 5.11 < 5.11.21, >= 5.12 < 5.12.4
Fixed versions
5.4.119, 5.10.37, 5.11.21, 5.12.4

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416
CVE-2021-47012 — Linux Linux, linux kernel | SECUFOCUS NOW