Linux Kernel up to 6.18.32/7.0.9 f2fs mm/filemap.c __filemap_get_folio+0x6bc/0xdc4 reference count

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.18.32/7.0.9. This issue affects the function __filemap_get_folio+0x6bc/0xdc4 of the file mm/filemap.c of the component f2fs. Performing a manipulation results in reference count. This vulnerability is reported as CVE-2026-53018. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.32/7.0.9. This affects the function __filemap_get_folio+0x6bc/0xdc4 of the file mm/filemap.c of the component f2fs. The manipulation with an unknown input leads to a reference count vulnerability. CWE is classifying the issue as CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: f2fs: avoid reading already updated pages during GC We found the following issue during fuzz testing: page: refcount:3 mapcount:0 mapping:00000000b6e89c65 index:0x18b2dc pfn:0x161ba9 memcg:f8ffff800e269c00 aops:f2fs_meta_aops ino:2 flags: 0x52880000000080a9(locked|waiters|uptodate|lru|private|zone=1|kasantag=0x4a) raw: 52880000000080a9 fffffffec6e17588 fffffffec0ccc088 a7ffff8067063618 raw: 000000000018b2dc 0000000000000009 00000003ffffffff f8ffff800e269c00 page dumped because: VM_BUG_ON_FOLIO(folio_test_uptodate(folio)) page_owner tracks the page as allocated post_alloc_hook+0x58c/0x5ec prep_new_page+0x34/0x284 get_page_from_freelist+0x2dcc/0x2e8c __alloc_pages_noprof+0x280/0x76c __folio_alloc_noprof+0x18/0xac __filemap_get_folio+0x6bc/0xdc4 pagecache_get_page+0x3c/0x104 do_garbage_collect+0x5c78/0x77a4 f2fs_gc+0xd74/0x25f0 gc_thread_func+0xb28/0x2930 kthread+0x464/0x5d8 ret_from_fork+0x10/0x20 ------------[ cut here ]------------ kernel BUG at mm/filemap.c:1563! folio_end_read+0x140/0x168 f2fs_finish_read_bio+0x5c4/0xb80 f2fs_read_end_io+0x64c/0x708 bio_endio+0x85c/0x8c0 blk_update_request+0x690/0x127c scsi_end_request+0x9c/0xb8c scsi_io_completion+0xf0/0x250 scsi_finish_command+0x430/0x45c scsi_complete+0x178/0x6d4 blk_mq_complete_request+0xcc/0x104 scsi_done_internal+0x214/0x454 scsi_done+0x24/0x34 which is similar to the problem reported by syzbot: https://syzkaller.appspot.com/bug?extid=3686758660f980b402dc This case is consistent with the description in commit 9bf1a3f ("f2fs: avoid GC causing encrypted file corrupted"): Page 1 is moved from blkaddr A to blkaddr B by move_data_block, and after being written it is marked as uptodate. Then, Page 1 is moved from blkaddr B to blkaddr C, VM_BUG_ON_FOLIO was triggered in the endio initiated by ra_data_block. There is no need to read Page 1 again from blkaddr B, since it has already been updated. Therefore, avoid initiating I/O in this case.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-53018 since 06/09/2026. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/24/2026).

Upgrading to version 6.18.33 or 7.0.10 eliminates this vulnerability. Applying the patch 4623c251496b99c530ce225c05334f4eac8b933a/b663ebb8a340eae5442e605b6acd2cff5677f016/570e2ccc7cb35fe720106964e65060602d3d2ac4 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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