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VulnerabilityPublished Updated

CVE-2025-21888: Linux kernel · RDMA/mlx5: Fix a WARN during dereg_mr for DM type

Affects Linux kernelSource GCVE Database

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Authoritative record:CVE-2025-21888· Low

Not known to be exploited · CVSS 5.5 Low · fixed in 5.15.0-1092.99~20.04.1 : update Linux kernel when convenient.

Data as of 12 Nov 2026, 19:33 UTC

CVSS 3.1 base score
5.5Low
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
Patch
Available – fixed in 5.15.0-1092.99~20.04.1, 5.15.0-1096.105~20.04.1, 5.15.0-1092.101~20.04.1 +63
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-84.84
Fixed in
  • 6.8.0-84.84
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1039.41
Fixed in
  • 6.8.0-1039.41
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1038.44
Fixed in
  • 6.8.0-1038.44
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-1015.15~24.04.1
Fixed in
  • 6.11.0-1015.15~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1016.17
Fixed in
  • 6.8.0-1016.17
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1040.42
Fixed in
  • 6.8.0-1040.42

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and included in multiple fixed Linux kernel versions (e.g., 5.15.0-1092.99~20.04.1 and later). Users should update their Linux kernel to one of the fixed versions provided by their distribution. After updating, a system reboot is required to apply the fix. No additional mitigations are necessary as the issue is resolved by the official patch.

Description

A vulnerability in the Linux kernel's RDMA mlx5 driver caused a warning during deregistration of device memory (DM) type memory regions. The issue was due to incorrect handling of DMA unmapping for DM type memory regions, leading to a WARN message in the kernel logs. This has been fixed by correcting the code path to properly handle DM type memory regions during deregistration.

References

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