High 7.8Published May 1, 2026

CVE-2026-31715f2fs: fix UAF caused by decrementing sbi->nr_pages[] in f2fs_write_end_io()

Updated under an hour ago (Oct 27, 2026, 7:40 PM ET)

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Exploited in the last 30 days

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.

CVSS: 7.8 HIGH (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Jun 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	50fa53eccf9f911a5b435248a2b0bd484fd82e5e builds before 7dbdab4430e4654db9aacef12b9b3b8b29ca25cb; from 50fa53eccf9f911a5b435248a2b0bd484fd82e5e before ffb94770dbdfb5411be5d9f44a960b010ec890ad; 50fa53eccf9f911a5b435248a2b0bd484fd82e5e builds before 0d40b26377f891e6dcb6efaf8ef9374c99be1b1d; from 50fa53eccf9f911a5b435248a2b0bd484fd82e5e before 1171f329cf1c175321251ac40fd126150d7ad1e8; 50fa53eccf9f911a5b435248a2b0bd484fd82e5e builds before 7be222de96c0f9eee6e65eeb017ef855ee185cfa; from 50fa53eccf9f911a5b435248a2b0bd484fd82e5e before 963d2e24d9d92a31e6773b0f642214f10013ebf7; from 50fa53eccf9f911a5b435248a2b0bd484fd82e5e before 188bb65f247a7a7c62f287c9a263aee3cad96fa5; 50fa53eccf9f911a5b435248a2b0bd484fd82e5e builds before 2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53	CNA record
linux linux_kernel linux:linux_kernel	from 4.19 before 6.18.25; from 6.19 before 7.0.2; 7.1	NVD

References

References

https://git.kernel.org/stable/c/7dbdab4430e4654db9aacef12b9b3b8b29ca25cb
https://git.kernel.org/stable/c/ffb94770dbdfb5411be5d9f44a960b010ec890ad
https://git.kernel.org/stable/c/0d40b26377f891e6dcb6efaf8ef9374c99be1b1d
https://git.kernel.org/stable/c/1171f329cf1c175321251ac40fd126150d7ad1e8
https://git.kernel.org/stable/c/7be222de96c0f9eee6e65eeb017ef855ee185cfa
https://git.kernel.org/stable/c/963d2e24d9d92a31e6773b0f642214f10013ebf7	patch
https://git.kernel.org/stable/c/188bb65f247a7a7c62f287c9a263aee3cad96fa5	patch
https://git.kernel.org/stable/c/2d9c4a4ed4eef1f82c5b16b037aee8bad819fd53	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.