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VulnerabilityPublished Updated

CVE-2025-21800: Linux kernel · net/mlx5: HWS, fix definer's HWS_SET32 macro for negative offset

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.8 High.

Data as of 29 Oct 2026, 23:41 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 27 Feb 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 29 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinux-raspi-realtimepkg:deb/ubuntu/linux-raspi-realtime?arch=source&distro=nobleOther threatsAffected
  • =6.8.0-2019.20
Fixed in–
Ubuntu 22.04 LTSlinux-allwinner-5.19pkg:deb/ubuntu/linux-allwinner-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1007.7~22.04.1 – 5.19.0-1015.15~22.04.1
8 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-5.19pkg:deb/ubuntu/linux-aws-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1019.20~22.04.1 – 5.19.0-1029.30~22.04.1
10 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-6.2pkg:deb/ubuntu/linux-aws-6.2?arch=source&distro=jammyOther threatsAffected
  • 6.2.0-1005.5~22.04.1 – 6.2.0-1018.18~22.04.1
14 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-6.5pkg:deb/ubuntu/linux-aws-6.5?arch=source&distro=jammyOther threatsAffected
  • 6.5.0-1008.8~22.04.1 – 6.5.0-1024.24~22.04.1
14 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-azure-5.19pkg:deb/ubuntu/linux-azure-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1020.21~22.04.1 – 5.19.0-1027.30~22.04.2
7 affected builds
Fixed in–

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

AI-suggested

A fix for this vulnerability is available as it has been resolved in the affected Linux kernel versions listed. Users should update to patched kernel versions to remediate the issue. Since this is not a cloud service, manual patching is required. No indication of no-action or automatic mitigation is provided, so applying the official kernel updates is recommended.

Description

CVE-2025-21800 is a high-severity vulnerability in the Linux kernel's net/mlx5 driver related to the HWS_SET32 macro. The issue arises when the macro is used with a negative bit offset, causing a shift-out-of-bounds error detected by UBSAN (Undefined Behavior Sanitizer). This flaw affects multiple specific versions of the Linux kernel, including various Ubuntu HWE edge releases. The vulnerability has a CVSS score of 7.8, indicating a significant impact on confidentiality, integrity, and availability.

References

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