PT-2026-5521 · Btrfs+1 · Btrfs+1

Published 2026-01-01 · Updated 2026-03-25 · CVE-2026-23018

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 The Linux kernel contained a flaw in the btrfs subsystem where the path was released before the extent tree was initialized within the btrfs read locked inode() function. This could lead to a circular lock dependency, triggering a lockdep warning. The issue arises when calling btrfs init file extent tree() while holding a read-locked leaf from a subvolume tree, potentially causing a GFP KERNEL allocation and triggering reclaim. This circular dependency was observed during file system synchronization and inode eviction processes.

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

Exploit

Allocation of Resources Without Limits

Weakness Enumeration

CWE-770

Related Identifiers

BDU:2026-04098

CVE-2026-23018

OPENSUSE-SU-2026:20416-1

SUSE-SU-2026:20838-1

SUSE-SU-2026:20931-1

SUSE-SU-2026:21284-1

Affected Products

Linux Kernel

Btrfs

References · 397

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23018.json · Exploit
• https://cve.org/CVERecord?id=CVE-2026-23018 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2026:20838-1 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-23018 · Vendor Advisory
• https://git.kernel.org/stable/c/8731f2c50b0b1d2b58ed5b9671ef2c4bdc2f8347 · Patch
• https://osv.dev/vulnerability/CVE-2026-23018 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-04098 · Security Note
• https://ubuntu.com/security/CVE-2026-23018 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:20931-1 · Vendor Advisory
• https://git.kernel.org/stable/c/92a5590851144f034adc51fee55e6878ccac716e · Patch
• https://security-tracker.debian.org/tracker/CVE-2026-23018 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:20416-1 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-23018 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23018 · Security Note
• https://suse.com/security/cve/CVE-2026-23121 · Note