In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io()
The xfstests case "generic/107" and syzbot have both reported a NULL
pointer dereference.
The concurrent scenario that triggers the panic is as follows:
F2FS_WB_CP_DATA write callback umount
- f2fs_write_checkpoint
- f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA)
- blk_mq_end_request
- bio_endio
- f2fs_write_end_io
: dec_page_count(sbi, F2FS_WB_CP_DATA)
: wake_up(&sbi->cp_wait)
- kill_f2fs_super
- kill_block_super
- f2fs_put_super
: iput(sbi->node_inode)
: sbi->node_inode = NULL
: f2fs_in_warm_node_list
- is_node_folio // sbi->node_inode is NULL and panic
The root cause is that f2fs_put_super() calls iput(sbi->node_inode) and
sets sbi->node_inode to NULL after sbi->nr_pages[F2FS_WB_CP_DATA] is
decremented to zero. As a result, f2fs_in_warm_node_list() may
dereference a NULL node_inode when checking whether a folio belongs to
the node inode, leading to a panic.
This patch fixes the issue by calling f2fs_in_warm_node_list() before
decrementing sbi->nr_pages[F2FS_WB_CP_DATA], thus preventing the
use-after-free condition.
References
Configurations
Configuration 1 (hide)
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History
17 May 2026, 16:16
| Type | Values Removed | Values Added |
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| References |
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07 May 2026, 06:16
| Type | Values Removed | Values Added |
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| References |
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06 May 2026, 21:11
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Linux
Linux linux Kernel |
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| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| CWE | CWE-416 | |
| CPE | cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
|
| References | () https://git.kernel.org/stable/c/188bb65f247a7a7c62f287c9a263aee3cad96fa5 - Patch | |
| References | () https://git.kernel.org/stable/c/2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53 - Patch | |
| References | () https://git.kernel.org/stable/c/963d2e24d9d92a31e6773b0f642214f10013ebf7 - Patch |
01 May 2026, 14:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-01 14:16
Updated : 2026-05-17 16:16
NVD link : CVE-2026-31715
Mitre link : CVE-2026-31715
CVE.ORG link : CVE-2026-31715
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free
