PT-2025-47717 · Linux+4 · Linux Kernel+4

Published 2025-10-26 · Updated 2026-03-13 · CVE-2025-40209

Positive Technologies (AI Summary)

CVSS v2.0

4.6

Medium

Base vector

AV:L/AC:L/Au:S/C:N/I:N/A:C

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

Description A memory leak exists in the btrfs file system within the Linux kernel, specifically in the btrfs add qgroup relation function. This occurs when the function is called with invalid qgroup levels where the source level is greater than or equal to the destination level. In such cases, the function returns an error without freeing a preallocated qgroup list structure. The caller unconditionally sets the pointer to NULL after the call, preventing cleanup, leading to a memory leak. This can be repeatedly triggered by a user with access to a writable btrfs mount, potentially exhausting kernel memory. The vulnerable code pattern is present in btrfs ioctl qgroup assign(). The leak involves 64 bytes per failed operation.

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

Exploit

Memory Leak

Weakness Enumeration

CWE-401

Related Identifiers

BDU:2025-14899

CVE-2025-40209

OPENSUSE-SU-2026:20145-1

SUSE-SU-2026:20207-1

SUSE-SU-2026:20220-1

SUSE-SU-2026:20228-1

USN-8029-1

USN-8029-2

USN-8029-3

USN-8030-1

USN-8048-1

Affected Products

Debian

Linuxmint

Linux Kernel

Ubuntu

Btrfs

References · 866

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40209.json · Exploit
• https://ubuntu.com/security/CVE-2025-40217 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40166 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40063 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40035 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40049 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40185 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-68246 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-68200 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40045 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40229 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2025-40209 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40053 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40193 · Vendor Advisory
• https://ubuntu.com/security/CVE-2025-40244 · Vendor Advisory