CVE-2025-21662

Task hang via incomplete mlx5 command completion

Published Jan 21, 2025 · Updated May 23, 2026

Denial of service in the mlx5 driver in affected Linux kernels allows local users to hang a task issuing a device command. When cmd_alloc_index() fails, cmd_work_handler() returns without completing ent->slotted, so cmd_exec() waits indefinitely for completion. Reachability requires the mlx5 driver and exhaustion of firmware command slots; the documented consequence is a blocked task, not a system crash.

CVSS severity5.5
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the mlx5 driver in affected Linux kernels allows local users to hang a task issuing a device command. When cmd_alloc_index() fails, cmd_work_handler() returns without completing ent->slotted, so cmd_exec() waits indefinitely for completion. Reachability requires the mlx5 driver and exhaustion of firmware command slots; the documented consequence is a blocked task, not a system crash.

The record

CVE
CVE-2025-21662
Published
Jan 21, 2025
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2025CVE 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=2d0962d05c93de391ce85f6e764df895f47c8918
  2. Affected versionversion=485d65e1357123a697c591a5aeb773994b247ad7 <0e2909c6bec9048f49d0c8e16887c63b50b14647
  3. Affected versionversion=485d65e1357123a697c591a5aeb773994b247ad7 <36124081f6ffd9dfaad48830bdf106bb82a9457d
  4. Affected versionversion=4baae687a20ef2b82fde12de3c04461e6f2521d6 <f0a2808767ac39f64b1d9a0ff865c255073cf3d4
  5. Affected versionversion=6.10
  6. Affected versionversion=6.1.93 <6.1.125
  7. Affected versionversion=6.6.33 <6.6.72
  8. Affected versionversion=6.8.12 <6.9
  9. Affected versionversion=6.9.3 <6.10
  10. Affected versionversion=94024332a129c6e4275569d85c0c1bfb2ae2d71b
  11. Affected versionversion=f9caccdd42e999b74303c9b0643300073ed5d319 <229cc10284373fbe754e623b7033dca7e7470ec8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2d0962d05c93de391ce85f6e764df895f47c8918; version=485d65e1357123a697c591a5aeb773994b247ad7 <0e2909c6bec9048f49d0c8e16887c63b50b14647; version=485d65e1357123a697c591a5aeb773994b247ad7 <36124081f6ffd9dfaad48830bdf106bb82a9457d; version=4baae687a20ef2b82fde12de3c04461e6f2521d6 <f0a2808767ac39f64b1d9a0ff865c255073cf3d4; version=6.10; version=6.1.93 <6.1.125; version=6.6.33 <6.6.72; version=6.8.12 <6.9; version=6.9.3 <6.10; version=94024332a129c6e4275569d85c0c1bfb2ae2d71b; version=f9caccdd42e999b74303c9b0643300073ed5d319 <229cc10284373fbe754e623b7033dca7e7470ec8

Published CVSS scores

5.5NIST NVDCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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