CVE-2026-23018
Description
A potential deadlock vulnerability was found in the Linux kernel's Btrfs filesystem. In btrfs_read_locked_inode(), the function calls btrfs_init_file_extent_tree() while holding a read-locked leaf from the subvolume tree. Since btrfs_init_file_extent_tree() may perform GFP_KERNEL memory allocation, it can trigger memory reclaim which creates a circular lock dependency between the btree lock, fs_reclaim, and the delayed_node mutex.
Statement
This is a lockdep-detected circular locking dependency that can theoretically cause a deadlock under memory pressure. The chain involves: fs_reclaim → btrfs-tree lock → delayed_node mutex → fs_reclaim. While lockdep warns about this pattern, triggering an actual deadlock requires specific memory pressure conditions during inode lookup operations.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Other); DoS: Crash, Exit, or Restart
Each thread of execution will "hang" and prevent tasks from completing. In some cases, CPU consumption may occur if a lock check occurs in a tight loop.
Frequently Asked Questions
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