cbcvebase.
CVE-2025-71159
published 2026-01-23

CVE-2025-71159: In the Linux kernel, the following vulnerability has been resolved: btrfs: fix use-after-free warning in btrfs_get_or_create_delayed_node() Previously…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.21%
10.8th percentile
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.

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.18.8-1 (forky)linux 6.18.8-1 (forky)
linuxlinux
linuxlinux>= e8513c012de75fd65e2df5499572bc6ef3f6e409 < c8385851a5435f4006281828d428e5d0b0bbf8afc8385851a5435f4006281828d428e5d0b0bbf8af
linuxlinux>= e8513c012de75fd65e2df5499572bc6ef3f6e409 < 83f59076a1ae6f5c6845d6f7ed3a1a373d88368483f59076a1ae6f5c6845d6f7ed3a1a373d883684
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.18.8-16.18.8-1
linuxlinux_kernel>= 6.18 < 6.18.66.18.6

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8LOW
vendor_redhat7.8HIGH
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.