PT-2025-9004 · Linux+3 · Linux Kernel+3

Matt Fleming · Published 2025-02-07 · Updated 2025-05-07 · CVE-2025-21813

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 vulnerability in the Linux kernel has been identified, related to the timers/migration component. The issue arises from an off-by-one error when connecting a new root to the old root, resulting in the old root not being connected to the new root. This can lead to the system running with more than one top-level idle migrator, defeating its purpose. The problem is caused by the children counter of the new root not being correctly updated, leading to potential overcommit and incorrect initialization of the group mask. Although the issue is harmless in certain scenarios, it can still cause warnings and odd behavior.

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

Exploit

Race Condition

Weakness Enumeration

CWE-362

CWE-193

Related Identifiers

BDU:2025-11993

CVE-2025-21813

USN-7489-1

USN-7489-2

USN-7491-1

USN-7499-1

Affected Products

Astra Linux

Linuxmint

Linux Kernel

Ubuntu

References · 29

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21813.json · Exploit
• https://ubuntu.com/security/CVE-2025-21902 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2025-21813 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2025-21813 · Security Note
• https://ubuntu.com/security/CVE-2025-21953 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2025-21813 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-11993 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2025-21813 · Vendor Advisory
• https://osv.dev/vulnerability/USN-7489-1 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-7491-1 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-7499-1 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2025-21813 · Vendor Advisory
• https://git.kernel.org/stable/c/6f449d8fa1808a7f9ee644866bbc079285dbefdd · Patch
• https://wiki.astralinux.ru/astra-linux-se18-bulletin-2025-0811SE18 · Vendor Advisory
• https://git.kernel.org/stable/c/868c9037df626b3c245ee26a290a03ae1f9f58d3 · Patch