# CVE-2026-53018: f2fs: avoid reading already updated pages during GC

CVE-2026-53018 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-53018, released June 25, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-53018
- Priority: Urgent
- CVSS: 9.8 (Critical)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 24, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53018

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-53018](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53018.md) | Jun 25, 2026 |
| Linux | linux Debian 14 | 7.0.10-1 | [DEBIAN-CVE-2026-53018](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53018.md) | Jun 25, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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