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CVE Record

CVE-2026-43349: f2fs: fix to avoid uninit-value access in f2fs_sanity_check_node_footer

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to avoid uninit-value access in f2fs_sanity_check_node_footer syzbot reported a f2fs bug as below: BUG: KMSAN: uninit-value in f2fs_sanity_check_node_footer+0x374/0xa20 fs/f2fs/node.c:1520 f2fs_sanity_check_node_footer+0x374/0xa20 fs/f2fs/node.c:1520 f2fs_finish_read_bio+0xe1e/0x1d60 fs/f2fs/data.c:177 f2fs_read_end_io+0x6ab/0x2220 fs/f2fs/data.c:-1 bio_endio+0x1006/0x1160 block/bio.c:1792 submit_bio_noacct+0x533/0x2960 block/blk-core.c:891 submit_bio+0x57a/0x620 block/blk-core.c:926 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] f2fs_submit_read_bio+0x12c/0x360 fs/f2fs/data.c:557 f2fs_submit_page_bio+0xee2/0x1450 fs/f2fs/data.c:775 read_node_folio+0x384/0x4b0 fs/f2fs/node.c:1481 __get_node_folio+0x5db/0x15d0 fs/f2fs/node.c:1576 f2fs_get_inode_folio+0x40/0x50 fs/f2fs/node.c:1623 do_read_inode fs/f2fs/inode.c:425 [inline] f2fs_iget+0x1209/0x9380 fs/f2fs/inode.c:596 f2fs_fill_super+0x8f5a/0xb2e0 fs/f2fs/super.c:5184 get_tree_bdev_flags+0x6e6/0x920 fs/super.c:1694 get_tree_bdev+0x38/0x50 fs/super.c:1717 f2fs_get_tree+0x35/0x40 fs/f2fs/super.c:5436 vfs_get_tree+0xb3/0x5d0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3763 [inline] do_new_mount+0x885/0x1dd0 fs/namespace.c:3839 path_mount+0x7a2/0x20b0 fs/namespace.c:4159 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x704/0x7f0 fs/namespace.c:4338 __x64_sys_mount+0xe4/0x150 fs/namespace.c:4338 x64_sys_call+0x39f0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:166 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f The root cause is: in f2fs_finish_read_bio(), we may access uninit data in folio if we failed to read the data from device into folio, let's add a check condition to avoid such issue.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-43349 is a Linux kernel f2fs filesystem bug. When a device read fails, kernel code may inspect uninitialized data while processing f2fs node metadata. Public sources show upstream stable fixes, but do not provide CVSS, CWE, confirmed impact, or exploitation evidence.

Executive priority

Treat as a targeted kernel maintenance item, not an emergency based on current evidence. Prioritize patch validation for systems using f2fs, embedded Linux, mobile-like storage stacks, or removable media workflows.

Technical view

The issue is in f2fs_finish_read_bio() and f2fs_sanity_check_node_footer(). syzbot/KMSAN reported uninitialized-value access during f2fs mount/read paths after failed data reads into a folio. The fix adds a condition to avoid checking uninitialized folio data.

Likely exposure

Exposure is most relevant to Linux systems that support or mount f2fs filesystems. Risk is higher where f2fs media or images can be introduced from less-trusted sources. The provided affected-version data is limited and should be verified against distribution kernel advisories.

Exploitation context

No active exploitation is reported in the provided sources, and the CVE is not listed as KEV. The public record describes a syzbot-discovered kernel bug, not an exploit. Practical security impact is not fully characterized in the source bundle.

Researcher notes

The source data lacks CVSS, CWE, and detailed impact analysis. Affected-version metadata appears kernel-specific and should be reconciled with downstream backports. The three git.kernel.org stable commits are the primary remediation references.

Mitigation direction

  • Apply Linux kernel updates that include the referenced stable f2fs fixes.
  • Check your Linux distribution advisory for backported fixed kernel packages.
  • Prioritize systems that mount f2fs or accept removable/storage images.
  • If patch timing is unclear, ask the vendor for CVE-2026-43349 status.

Validation and detection

  • Inventory Linux kernels and identify systems with f2fs enabled or mounted.
  • Compare installed kernel packages against vendor advisories for CVE-2026-43349.
  • Verify whether referenced stable commits are present in your kernel source or changelog.
  • Review storage workflows that allow f2fs media or images to be mounted.
Prepared
Confidence
medium
Sources
5

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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CVE-2026-43349 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
4Source 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
LinuxLinux855c54f1803e3ebc613677b4f389c7f92656a1fc, 50ac3ecd8e05b6bcc350c71a4307d40c030ec7e4, 50ac3ecd8e05b6bcc350c71a4307d40c030ec7e4, c386753db52b3a80afa6612bfdcb925aa5ca260f, 6.18.13, 6.19.3unaffected
LinuxLinux7.0, 0, 6.18.25, 7.0.2, 7.1affected
Weakness

CWE details

No CWE listed

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