btrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node()
Summary
| CVE | CVE-2025-71159 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-01-23 16:15:52 UTC |
| Updated | 2026-07-30 06:24:54 UTC |
| Description | In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node() Previously, btrfs_get_or_create_delayed_node() set the delayed_node's refcount before acquiring the root->delayed_nodes lock. Commit e8513c012de7 ("btrfs: implement ref_tracker for delayed_nodes") moved refcount_set inside the critical section, which means there is no longer a memory barrier between setting the refcount and setting btrfs_inode->delayed_node. Without that barrier, the stores to node->refs and btrfs_inode->delayed_node may become visible out of order. Another thread can then read btrfs_inode->delayed_node and attempt to increment a refcount that hasn't been set yet, leading to a refcounting bug and a use-after-free warning. The fix is to move refcount_set back to where it was to take advantage of the implicit memory barrier provided by lock acquisition. Because the allocations now happen outside of the lock's critical section, they can use GFP_NOFS instead of GFP_ATOMIC. |
Risk And Classification
Primary CVSS: v3.1 7.8 HIGH from [email protected]
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.002060000 probability, percentile 0.107880000 (date 2026-08-01)
Problem Types: CWE-416
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.8 | HIGH | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 9.8 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Operating System | Linux | Linux Kernel | All | All | All | All |
| Operating System | Linux | Linux Kernel | 6.19 | rc1 | All | All |
| Operating System | Linux | Linux Kernel | 6.19 | rc2 | All | All |
| Operating System | Linux | Linux Kernel | 6.19 | rc3 | All | All |
| Operating System | Linux | Linux Kernel | 6.19 | rc4 | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected e8513c012de75fd65e2df5499572bc6ef3f6e409 c8385851a5435f4006281828d428e5d0b0bbf8af git | Not specified |
| CNA | Linux | Linux | affected e8513c012de75fd65e2df5499572bc6ef3f6e409 83f59076a1ae6f5c6845d6f7ed3a1a373d883684 git | Not specified |
| CNA | Linux | Linux | affected 6.18 | Not specified |
| CNA | Linux | Linux | unaffected 6.18 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.6 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.19 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/83f59076a1ae6f5c6845d6f7ed3a1a373d883684 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| git.kernel.org/stable/c/c8385851a5435f4006281828d428e5d0b0bbf8af | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | Patch |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.