EUVD-2026-26524CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
7DescriptionNVD
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.
AnalysisAI
Use-after-free in Linux kernel F2FS filesystem allows local authenticated attackers to trigger kernel panic or potentially achieve code execution. The vulnerability (CWE-416) occurs during concurrent write callback and unmount operations when f2fs_write_end_io() decrements page count before checking node inode validity, leading to NULL pointer dereference. …
Sign in for full analysis, threat intelligence, and remediation guidance.
RemediationAI
Within 24 hours: Inventory all Linux systems using F2FS filesystem and identify current kernel versions. Within 7 days: Apply vendor patches-kernel 6.18.25, 7.0.2, or 7.1-rc1 depending on your current branch-to all affected systems, prioritizing production environments. …
Sign in for detailed remediation steps.
More from same product – last 7 days
Kernel availability loss in Ubuntu Linux 6.8, 6.17, and 7.0 can be triggered by any unprivileged local user via a defect
Kernel panic via NULL pointer dereference in Ubuntu Linux 6.8's AppArmor notification handler allows a locally authentic
NULL pointer dereference in Ubuntu Linux kernel versions 6.8, 6.17, and 7.0 allows a local unprivileged user to crash th
NULL pointer dereference in Ubuntu Linux kernel SAUCE patches (versions 6.8, 6.17, and 7.0) allows an unprivileged local
In the Linux kernel, the following vulnerability has been resolved: netfilter: arp_tables: fix IEEE1394 ARP payload par
Vendor StatusVendor
Share
External POC / Exploit Code
Leaving vuln.today