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CVE Record

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

In the Linux kernel, the following vulnerability has been resolved: drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl In the "pmcmd_ioctl" function, three memory objects allocated by kmalloc are initialized by "hcall_get_cpu_state", which are then copied to user space. The initializer is indeed implemented in "acrn_hypercall2" (arch/x86/include/asm/acrn.h). There is a risk of information leakage due to uninitialized bytes.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2025-21950 is a Linux kernel information-leak issue in the ACRN hypervisor service module. Memory allocated for a power-management ioctl could include uninitialized bytes before being copied to user space. The source bundle provides fixes but no CVSS score or confirmed exploitation.

Executive priority

Treat this as a targeted kernel hygiene item. Prioritize environments using ACRN virtualization or custom kernels, then fold remaining Linux updates into normal patch cycles. Escalate only if the ACRN interface is exposed to untrusted local users.

Technical view

In drivers/virt/acrn/hsm, pmcmd_ioctl allocated three objects with kmalloc, then hcall_get_cpu_state initialized them before copy_to_user. The CVE states acrn_hypercall2 may leave bytes uninitialized, creating a user-space disclosure risk. Stable kernel commits change allocation to kzalloc.

Likely exposure

Exposure appears limited to Linux kernels containing the ACRN HSM driver path and systems where that interface is built, loaded, and reachable. The bundle lists Linux kernel versions and stable commits, but does not define distribution-specific exposure beyond the Debian LTS notice.

Exploitation context

The bundle does not report active exploitation, and KEV is false. The issue is an information disclosure risk, not documented here as privilege escalation or remote code execution. Practical impact depends on access to the relevant ACRN ioctl path and what residual memory may be disclosed.

Researcher notes

The available evidence identifies an uninitialized-memory disclosure in pmcmd_ioctl and the fix pattern, but not exploit prerequisites, leaked structure layout, or distribution coverage beyond Debian LTS. Avoid assuming broad reach without confirming ACRN HSM presence and ioctl accessibility.

Mitigation direction

  • Update to a kernel release containing the referenced stable fix commits.
  • Apply relevant distribution security updates, including Debian LTS updates where applicable.
  • Check vendor kernel advisories for exact fixed package versions.
  • Reduce access to ACRN HSM interfaces where they are not operationally required.

Validation and detection

  • Inventory Linux hosts for ACRN HSM driver usage and exposed device interfaces.
  • Compare running kernel builds against vendor-fixed releases or referenced stable commits.
  • Confirm Debian LTS systems received the relevant kernel security update.
  • Review kernel configuration for ACRN support on affected fleet segments.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-21950 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
8Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3d679d5aec648f50e645702929890b9611998a0b, 3d679d5aec648f50e645702929890b9611998a0b, 3d679d5aec648f50e645702929890b9611998a0b, 3d679d5aec648f50e645702929890b9611998a0b, 3d679d5aec648f50e645702929890b9611998a0b, 3d679d5aec648f50e645702929890b9611998a0bunaffected
LinuxLinux5.12, 0, 5.15.179, 6.1.131, 6.6.83, 6.12.19, 6.13.7, 6.14affected
Weakness

CWE details

No CWE listed

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