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CVE-2025-40054— f2fs: fix UAF issue in f2fs_merge_page_bio()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于f2fs_merge_page_bio函数中存在释放后重用问题，可能导致空指针取消引用。

CVSS 7.8 · High EPSS 0.17% · P6

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux 0b20fcec8651569935a10afe03fedc0b812d044e< 1f7b44b4a2b2939f08b279cbb9e6b5dcb8ffea32 affected
0b20fcec8651569935a10afe03fedc0b812d044e< e193d8953647c8b575830852aa5ea0995b98d2b1 affected
0b20fcec8651569935a10afe03fedc0b812d044e< 410337c2301ae78a081e1b5ebbe8ec374fef4cb6 affected
0b20fcec8651569935a10afe03fedc0b812d044e< 68e094232dfe5027c4fd2dcded93d2d6800bae04 affected
0b20fcec8651569935a10afe03fedc0b812d044e< 7dd611131d82d7fc4212b555eb1103160bdad302 affected
0b20fcec8651569935a10afe03fedc0b812d044e< 01118321e0c8a5f3ece57d0d377bfc92d83cd210 affected
0b20fcec8651569935a10afe03fedc0b812d044e< edf7e9040fc52c922db947f9c6c36f07377c52ea affected
5.5 affected
… +8 more rows
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I. Basic Information for CVE-2025-40054

Vulnerability Information
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Vulnerability Title
f2fs: fix UAF issue in f2fs_merge_page_bio()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix UAF issue in f2fs_merge_page_bio() As JY reported in bugzilla [1], Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 pc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98 lr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4 CPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P B W OE 6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5 Tainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Workqueue: writeback wb_workfn (flush-254:49) Call trace: f2fs_is_cp_guaranteed+0x70/0x98 f2fs_inplace_write_data+0x174/0x2f4 f2fs_do_write_data_page+0x214/0x81c f2fs_write_single_data_page+0x28c/0x764 f2fs_write_data_pages+0x78c/0xce4 do_writepages+0xe8/0x2fc __writeback_single_inode+0x4c/0x4b4 writeback_sb_inodes+0x314/0x540 __writeback_inodes_wb+0xa4/0xf4 wb_writeback+0x160/0x448 wb_workfn+0x2f0/0x5dc process_scheduled_works+0x1c8/0x458 worker_thread+0x334/0x3f0 kthread+0x118/0x1ac ret_from_fork+0x10/0x20 [1] https://bugzilla.kernel.org/show_bug.cgi?id=220575 The panic was caused by UAF issue w/ below race condition: kworker - writepages - f2fs_write_cache_pages - f2fs_write_single_data_page - f2fs_do_write_data_page - f2fs_inplace_write_data - f2fs_merge_page_bio - add_inu_page : cache page #1 into bio & cache bio in io->bio_list - f2fs_write_single_data_page - f2fs_do_write_data_page - f2fs_inplace_write_data - f2fs_merge_page_bio - add_inu_page : cache page #2 into bio which is linked in io->bio_list write - f2fs_write_begin : write page #1 - f2fs_folio_wait_writeback - f2fs_submit_merged_ipu_write - f2fs_submit_write_bio : submit bio which inclues page #1 and #2 software IRQ - f2fs_write_end_io - fscrypt_free_bounce_page : freed bounced page which belongs to page #2 - inc_page_count( , WB_DATA_TYPE(data_folio), false) : data_folio points to fio->encrypted_page the bounced page can be freed before accessing it in f2fs_is_cp_guarantee() It can reproduce w/ below testcase: Run below script in shell #1: for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \ -c "pwrite 0 32k" -c "fdatasync" Run below script in shell #2: for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \ -c "pwrite 0 32k" -c "fdatasync" So, in f2fs_merge_page_bio(), let's avoid using fio->encrypted_page after commit page into internal ipu cache.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于f2fs_merge_page_bio函数中存在释放后重用问题，可能导致空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 0b20fcec8651569935a10afe03fedc0b812d044e ~ 1f7b44b4a2b2939f08b279cbb9e6b5dcb8ffea32 -
Linux Linux 5.5 -

II. Public POCs for CVE-2025-40054

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III. Intelligence Information for CVE-2025-40054

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Patches & Fixes for CVE-2025-40054 (4)

Same Patch Batch · Linux · 2025-10-28 · 58 CVEs total

CVE-2025-40074 9.8 CRITICAL ipv4: start using dst_dev_rcu()
CVE-2025-40058 8.8 HIGH iommu/vt-d: Disallow dirty tracking if incoherent page walk
CVE-2025-40039 8.8 HIGH ksmbd: Fix race condition in RPC handle list access
CVE-2025-40043 8.8 HIGH net: nfc: nci: Add parameter validation for packet data
CVE-2025-40046 8.6 HIGH io_uring/zcrx: fix overshooting recv limit
CVE-2025-40068 8.4 HIGH fs: ntfs3: Fix integer overflow in run_unpack()
CVE-2025-40075 8.1 HIGH tcp_metrics: use dst_dev_net_rcu()
CVE-2025-40026 7.9 HIGH KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O
CVE-2025-40025 7.8 HIGH f2fs: fix to do sanity check on node footer for non inode dnode
CVE-2025-40044 7.8 HIGH fs: udf: fix OOB read in lengthAllocDescs handling
CVE-2025-40045 7.8 HIGH ASoC: codecs: wcd937x: set the comp soundwire port correctly
CVE-2025-40041 7.8 HIGH LoongArch: BPF: Sign-extend struct ops return values properly
CVE-2025-40051 7.8 HIGH vhost: vringh: Modify the return value check
CVE-2025-40047 7.8 HIGH io_uring/waitid: always prune wait queue entry in io_waitid_wait()
CVE-2025-40061 7.8 HIGH RDMA/rxe: Fix race in do_task() when draining
CVE-2025-40027 7.8 HIGH net/9p: fix double req put in p9_fd_cancelled
CVE-2025-40028 7.8 HIGH binder: fix double-free in dbitmap
CVE-2025-40081 7.8 HIGH perf: arm_spe: Prevent overflow in PERF_IDX2OFF()
CVE-2025-40079 7.8 HIGH riscv, bpf: Sign extend struct ops return values properly
CVE-2025-40067 7.8 HIGH fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist

Showing top 20 of 58 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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