CVE-2021-47012

Local privilege escalation via SIW memory-registration use-after-free

Published Feb 28, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux kernel Soft-iWARP driver allows local users to gain kernel privileges through RDMA memory registration. siw_mr_add_mem assigns mem to mr->mem before xa_alloc_cyclic can fail and free mem, so siw_alloc_mr later passes the dangling pointer to siw_mr_drop_mem. A normal local user with an available SIW device can trigger kernel memory corruption, arbitrary kernel reads and writes, or a kernel crash without user interaction.

CVSS severity7.8
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux kernel Soft-iWARP driver allows local users to gain kernel privileges through RDMA memory registration. siw_mr_add_mem assigns mem to mr->mem before xa_alloc_cyclic can fail and free mem, so siw_alloc_mr later passes the dangling pointer to siw_mr_drop_mem. A normal local user with an available SIW device can trigger kernel memory corruption, arbitrary kernel reads and writes, or a kernel crash without user interaction.

The record

CVE
CVE-2021-47012
Published
Feb 28, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <3093ee182f01689b89e9f8797b321603e5de4f63
  2. Affected versionversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <30b9e92d0b5e5d5dc1101ab856c17009537cbca4
  3. Affected versionversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <3e22b88e02c194f6c80867abfef5cc09383461f4
  4. Affected versionversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <608a4b90ece039940e9425ee2b39c8beff27e00c
  5. Affected versionversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <ad9ce7188432650469a6c7625bf479f5ed0b6155
  6. Affected versionversion=5.3

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2251334dcac9eb337575d8767e2a6a7e81848f7f <3093ee182f01689b89e9f8797b321603e5de4f63; version=2251334dcac9eb337575d8767e2a6a7e81848f7f <30b9e92d0b5e5d5dc1101ab856c17009537cbca4; version=2251334dcac9eb337575d8767e2a6a7e81848f7f <3e22b88e02c194f6c80867abfef5cc09383461f4; version=2251334dcac9eb337575d8767e2a6a7e81848f7f <608a4b90ece039940e9425ee2b39c8beff27e00c; version=2251334dcac9eb337575d8767e2a6a7e81848f7f <ad9ce7188432650469a6c7625bf479f5ed0b6155; version=5.3

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.7SUSECVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
5.1Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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