PT-2025-10071 · Linux+9 · Linux Kernel+9

John Stultz · Published 2025-02-12 · Updated 2026-05-26 · CVE-2025-21839

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A bug in the Linux kernel's KVM (Kernel-based Virtual Machine) implementation allows the guest's DR6 value to be clobbered when the guest modifies DR6 and then a fastpath VM-Exit occurs. This issue primarily affects nested VMX setups, where the window between hardware DR6 being modified and DR6 being read by guest software is larger. The bug can cause the guest's actual DR6 value to be lost.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Improper Initialization

Weakness Enumeration

CWE-665

Related Identifiers

ALSA-2025:20518

BDU:2025-12248

CVE-2025-21839

DLA-4271-1

DSA-5925-1

ECHO-7E27-4885-0E91

INFSA-2025_20518

OESA-2025-2077

OESA-2025-2078

OESA-2025-2079

OPENSUSE-SU-2025_01620-1

OPENSUSE-SU-2025_01640-1

OPENSUSE-SU-2025_1195-1

RHSA-2025:20518

RHSA-2025_20518

SUSE-SU-2025:01620-1

SUSE-SU-2025:01640-1

SUSE-SU-2025:02853-1

SUSE-SU-2025:02923-1

SUSE-SU-2025:02969-1

SUSE-SU-2025:02996-1

SUSE-SU-2025:02997-1

SUSE-SU-2025:03011-1

SUSE-SU-2025:03023-1

SUSE-SU-2025:1183-1

SUSE-SU-2025:1195-1

SUSE-SU-2025:20577-1

SUSE-SU-2025:20586-1

SUSE-SU-2025:20601-1

SUSE-SU-2025:20602-1

SUSE-SU-2025_01620-1

SUSE-SU-2025_02853-1

SUSE-SU-2025_02969-1

SUSE-SU-2025_02996-1

SUSE-SU-2025_02997-1

SUSE-SU-2025_03011-1

SUSE-SU-2025_03023-1

SUSE-SU-2025_1195-1

USN-7521-1

USN-7521-2

USN-7521-3

USN-7654-1

USN-7654-2

USN-7654-3

USN-7654-4

USN-7654-5

USN-7655-1

USN-7686-1

USN-7703-1

USN-7703-2

USN-7703-3

USN-7703-4

USN-7711-1

USN-7712-1

USN-7712-2

USN-7719-1

USN-7737-1

Affected Products

Almalinux

Astra Linux

Debian

Linuxmint

Linux Kernel

Red Hat

Red Os

Rocky Linux

Suse

Ubuntu

References · 3089

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21839.json · Exploit
• https://ubuntu.com/security/CVE-2024-38541 · Vendor Advisory
• https://linux.oracle.com/errata/ELSA-2025-20530.html · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21793 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-38068 · Security Note
• https://ubuntu.com/security/CVE-2025-38083 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-23157 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21707 · Vendor Advisory
• https://ubuntu.com/security/CVE-2024-46751 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-38112 · Security Note
• https://ubuntu.com/security/CVE-2025-21867 · Vendor Advisory
• https://osv.dev/vulnerability/USN-7655-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21783 · Vendor Advisory
• https://ubuntu.com/security/CVE-2024-58007 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-21938 · Vendor Advisory