PT-2025-7950 · Linux+5 · Linux Kernel+5

Sean Christopherson · Published 2022-02-10 · Updated 2025-05-21 · CVE-2021-47639

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

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

Description A vulnerability in the Linux kernel has been identified, specifically in the KVM (Kernel-based Virtual Machine) component. The issue arises when unmapping a GFN (Guest Frame Number) range in the TDP MMU, where KVM fails to zap all roots, including invalid ones. This can lead to use-after-free and other issues if the mmu notifier runs to completion while an invalid root zapper yields. The bug can be reproduced by causing a collision between set nx huge pages() and kvm mmu notifier release().

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

DoS

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

BDU:2025-04346

CESA-2022_7683

CVE-2021-47639

OESA-2025-1318

RHSA-2022:7683

RHSA-2022:8267

RHSA-2022_7683

RHSA-2022_8267

SUSE-SU-2025:1027-1

SUSE-SU-2025:1176-1

SUSE-SU-2025:1183-1

SUSE-SU-2025:1241-1

SUSE-SU-2025_1027-1

SUSE-SU-2025_1241-1

Affected Products

Astra Linux

Centos

Linux Kernel

Red Hat

Red Os

Suse

References · 1339

• https://osv.dev/vulnerability/OESA-2025-1318 · Vendor Advisory
• https://git.kernel.org/stable/c/0c8a8da182d4333d9bbb9131d765145568c847b2 · Patch
• https://osv.dev/vulnerability/CVE-2021-47639 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-47639 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2025:1183-1 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2021-47639 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2025:1176-1 · Vendor Advisory
• https://git.kernel.org/stable/c/af47248407c0c5ae52a752af1ab5ce5b0db91502 · Patch
• https://security-tracker.debian.org/tracker/CVE-2021-47639 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2024-58058 · Security Note
• https://git.kernel.org/stable/c/d62007edf01f5c11f75d0f4b1e538fc52a5b1982 · Patch
• https://osv.dev/vulnerability/SUSE-SU-2025:1241-1 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2025:1027-1 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47639 · Vendor Advisory
• https://git.kernel.org/stable/c/8cf6f98ab1d16d5e607635a0c21c4231eb15367e · Patch