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CVE Record

CVE-2023-53763: Revert "f2fs: fix to do sanity check on extent cache correctly"

In the Linux kernel, the following vulnerability has been resolved: Revert "f2fs: fix to do sanity check on extent cache correctly" syzbot reports a f2fs bug as below: UBSAN: array-index-out-of-bounds in fs/f2fs/f2fs.h:3275:19 index 1409 is out of range for type '__le32[923]' (aka 'unsigned int[923]') Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:217 [inline] __ubsan_handle_out_of_bounds+0x11c/0x150 lib/ubsan.c:348 inline_data_addr fs/f2fs/f2fs.h:3275 [inline] __recover_inline_status fs/f2fs/inode.c:113 [inline] do_read_inode fs/f2fs/inode.c:480 [inline] f2fs_iget+0x4730/0x48b0 fs/f2fs/inode.c:604 f2fs_fill_super+0x640e/0x80c0 fs/f2fs/super.c:4601 mount_bdev+0x276/0x3b0 fs/super.c:1391 legacy_get_tree+0xef/0x190 fs/fs_context.c:611 vfs_get_tree+0x8c/0x270 fs/super.c:1519 do_new_mount+0x28f/0xae0 fs/namespace.c:3335 do_mount fs/namespace.c:3675 [inline] __do_sys_mount fs/namespace.c:3884 [inline] __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3861 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The issue was bisected to: commit d48a7b3a72f121655d95b5157c32c7d555e44c05 Author: Chao Yu <chao@kernel.org> Date: Mon Jan 9 03:49:20 2023 +0000 f2fs: fix to do sanity check on extent cache correctly The root cause is we applied both v1 and v2 of the patch, v2 is the right fix, so it needs to revert v1 in order to fix reported issue. v1: commit d48a7b3a72f1 ("f2fs: fix to do sanity check on extent cache correctly") https://lore.kernel.org/lkml/20230109034920.492914-1-chao@kernel.org/ v2: commit 269d11948100 ("f2fs: fix to do sanity check on extent cache correctly") https://lore.kernel.org/lkml/20230207134808.1827869-1-chao@kernel.org/

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2023-53763 is a Linux kernel F2FS filesystem bug. A prior patch was applied incorrectly alongside its replacement, causing an out-of-bounds access when mounting or reading an F2FS filesystem. The public record does not provide CVSS, confirmed impact beyond the reported crash condition, or evidence of active exploitation.

Executive priority

Treat as a targeted kernel maintenance item, not an emergency based on current evidence. Prioritize faster where F2FS is used or untrusted filesystem images may be mounted.

Technical view

The reported failure is UBSAN array-index-out-of-bounds in fs/f2fs/f2fs.h during f2fs_iget and f2fs_fill_super. The root cause is that both v1 and v2 of an F2FS extent-cache sanity-check patch were applied; v2 was correct, so v1 needed reverting. Kernel stable commits are referenced as fixes.

Likely exposure

Exposure is most relevant to Linux systems with affected kernels that mount F2FS filesystems. Risk increases where users, removable media, disk images, or automation can cause untrusted F2FS volumes to be mounted.

Exploitation context

No KEV listing or cited source confirms active exploitation. The available evidence is a syzbot-discovered kernel bug triggered through F2FS mount/read paths, not a public exploit report.

Researcher notes

The record identifies the fix pattern as reverting commit d48a7b3a72f1 because commit 269d11948100 was the correct v2 fix. Affected-version data in the bundle is incomplete and should be reconciled with distribution backports.

Mitigation direction

  • Apply vendor kernel updates containing the referenced stable fixes or equivalent backports.
  • Avoid mounting untrusted F2FS filesystems until systems are patched.
  • Check Linux distribution advisories for package-specific fixed kernel versions.
  • Restrict mount privileges where operationally possible.

Validation and detection

  • Inventory systems running Linux kernels with F2FS enabled or in use.
  • Compare installed kernel builds against vendor advisories and referenced stable commits.
  • Review logs for F2FS mount failures or kernel UBSAN out-of-bounds reports.
  • Confirm whether removable media or disk-image workflows use F2FS.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2023-53763 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
5Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux85eb8b61dd4cfc7a839a0e86287b92ca6193444e, d48a7b3a72f121655d95b5157c32c7d555e44c05, d48a7b3a72f121655d95b5157c32c7d555e44c05, d48a7b3a72f121655d95b5157c32c7d555e44c05, a3d1fd01250ffca88c11e9bd8d19be779acc7557, 6.1.29, 6.2.5unaffected
LinuxLinux6.3, 0, 6.1.53, 6.4.16, 6.5.3, 6.6affected
Weakness

CWE details

No CWE listed

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