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VulnerabilityPublished Updated

CVE-2025-21950: Linux kernel · drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.1 High · fixed in 5.15.0-1084.91~20.04.1 : patch Linux kernel soon.

Data as of 12 Nov 2026, 19:32 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.15.0-1084.91~20.04.1, 5.15.0-1089.98~20.04.1, 5.15.0-1083.92~20.04.1 +66
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Apr 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
  • <6.11.0-1018.18~24.04.1
Fixed in
  • 6.11.0-1018.18~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidiapkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=nobleOther threatsAffected
  • <6.8.0-1025.27
Fixed in
  • 6.8.0-1025.27
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 has been released in multiple Linux kernel versions including 5.15.0-1084.91~20.04.1 and later. Users should update their Linux kernel to one of the fixed versions provided by their distribution. After applying the update, a system reboot is required to complete remediation. No additional mitigation steps are necessary beyond applying the official kernel update.

Description

CVE-2025-21950 is a high-severity vulnerability in the Linux kernel's ACRN hypervisor service module. It involves an information leak caused by uninitialized memory bytes in the pmcmd_ioctl function, where memory allocated by kmalloc is not fully zeroed before being copied to user space. This flaw was fixed by switching to kzalloc to ensure memory is zero-initialized, preventing leakage of potentially sensitive kernel data.

References

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