CVE-2021-47481

Local service crash via uninitialized ODP xarray

Published May 22, 2024 · Updated May 23, 2026

A kernel crash in the mlx5 RDMA driver in affected Linux builds allows local users to cause a service interrupt through ODP memory-region teardown. In reg_create(), an errant desc_size assignment leaves the mlx5_ib_mr ODP xarray uninitialized, so mlx5_ib_dereg_mr dereferences an invalid address during teardown. Reachability requires a local low-privileged user, an mlx5 RDMA configuration with ODP support, and creation and deregistration of an ODP memory region; the bounded consequence is a kernel crash and service interruption.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A kernel crash in the mlx5 RDMA driver in affected Linux builds allows local users to cause a service interrupt through ODP memory-region teardown. In reg_create(), an errant desc_size assignment leaves the mlx5_ib_mr ODP xarray uninitialized, so mlx5_ib_dereg_mr dereferences an invalid address during teardown. Reachability requires a local low-privileged user, an mlx5 RDMA configuration with ODP support, and creation and deregistration of an ODP memory region; the bounded consequence is a kernel crash and service interruption.

The record

CVE
CVE-2021-47481
Published
May 22, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 22, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=29f91bd26f3ba828a55cb446ecd44caacf0df026
  2. Affected versionversion=5.12.4 <5.13
  3. Affected versionversion=5.13
  4. Affected versionversion=a639e66703ee45745dc4057c7c2013ed9e1963a7 <5508546631a0f555d7088203dec2614e41b5106e
  5. Affected versionversion=a639e66703ee45745dc4057c7c2013ed9e1963a7 <5f6995295f65d1ee6f36d466d26afd98eb797afe

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=29f91bd26f3ba828a55cb446ecd44caacf0df026; version=5.12.4 <5.13; version=5.13; version=a639e66703ee45745dc4057c7c2013ed9e1963a7 <5508546631a0f555d7088203dec2614e41b5106e; version=a639e66703ee45745dc4057c7c2013ed9e1963a7 <5f6995295f65d1ee6f36d466d26afd98eb797afe

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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