CVE-2025-21950

Kernel memory disclosure via uninitialized ACRN buffers

Published Apr 1, 2025 · Updated May 11, 2026

Information disclosure in the Linux kernel ACRN HSM driver allows local users to read uninitialized kernel memory through an ioctl. pmcmd_ioctl allocates three buffers with kmalloc, hcall_get_cpu_state leaves bytes uninitialized, and the driver copies those bytes to user space. Exploitation requires local access to the ACRN HSM ioctl and exposes residual kernel-memory bytes without a reported integrity impact.

CVSS severity7.1
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Information disclosure in the Linux kernel ACRN HSM driver allows local users to read uninitialized kernel memory through an ioctl. pmcmd_ioctl allocates three buffers with kmalloc, hcall_get_cpu_state leaves bytes uninitialized, and the driver copies those bytes to user space. Exploitation requires local access to the ACRN HSM ioctl and exposes residual kernel-memory bytes without a reported integrity impact.

The record

CVE
CVE-2025-21950
Published
Apr 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1005
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 1, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <1b8f7a2caa7f9cdfd135e3f78eb9d7e36fb95083
  2. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <4e15cf870d2c748e45d45ffc4d5b1dc1b7d50120
  3. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <524f29d78c9bdeb49f31f5b0376a07d2fc5cf563
  4. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <819cec1dc47cdeac8f5dd6ba81c1dbee2a68c3bb
  5. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <a4c21b878f0e237f45209a324c903ea7fb05247d
  6. Affected versionversion=3d679d5aec648f50e645702929890b9611998a0b <d7e5031fe3f161c8eb5e84db1540bc4373ed861b
  7. Affected versionversion=5.12

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3d679d5aec648f50e645702929890b9611998a0b <1b8f7a2caa7f9cdfd135e3f78eb9d7e36fb95083; version=3d679d5aec648f50e645702929890b9611998a0b <4e15cf870d2c748e45d45ffc4d5b1dc1b7d50120; version=3d679d5aec648f50e645702929890b9611998a0b <524f29d78c9bdeb49f31f5b0376a07d2fc5cf563; version=3d679d5aec648f50e645702929890b9611998a0b <819cec1dc47cdeac8f5dd6ba81c1dbee2a68c3bb; version=3d679d5aec648f50e645702929890b9611998a0b <a4c21b878f0e237f45209a324c903ea7fb05247d; version=3d679d5aec648f50e645702929890b9611998a0b <d7e5031fe3f161c8eb5e84db1540bc4373ed861b; version=5.12

Published CVSS scores

7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1005Data from Local System

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo