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CVE Record

CVE-2022-50009: f2fs: fix null-ptr-deref in f2fs_get_dnode_of_data

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix null-ptr-deref in f2fs_get_dnode_of_data There is issue as follows when test f2fs atomic write: F2FS-fs (loop0): Can't find valid F2FS filesystem in 2th superblock F2FS-fs (loop0): invalid crc_offset: 0 F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=1, run fsck to fix. F2FS-fs (loop0): f2fs_check_nid_range: out-of-range nid=2, run fsck to fix. ================================================================== BUG: KASAN: null-ptr-deref in f2fs_get_dnode_of_data+0xac/0x16d0 Read of size 8 at addr 0000000000000028 by task rep/1990 CPU: 4 PID: 1990 Comm: rep Not tainted 5.19.0-rc6-next-20220715 #266 Call Trace: <TASK> dump_stack_lvl+0x6e/0x91 print_report.cold+0x49a/0x6bb kasan_report+0xa8/0x130 f2fs_get_dnode_of_data+0xac/0x16d0 f2fs_do_write_data_page+0x2a5/0x1030 move_data_page+0x3c5/0xdf0 do_garbage_collect+0x2015/0x36c0 f2fs_gc+0x554/0x1d30 f2fs_balance_fs+0x7f5/0xda0 f2fs_write_single_data_page+0xb66/0xdc0 f2fs_write_cache_pages+0x716/0x1420 f2fs_write_data_pages+0x84f/0x9a0 do_writepages+0x130/0x3a0 filemap_fdatawrite_wbc+0x87/0xa0 file_write_and_wait_range+0x157/0x1c0 f2fs_do_sync_file+0x206/0x12d0 f2fs_sync_file+0x99/0xc0 vfs_fsync_range+0x75/0x140 f2fs_file_write_iter+0xd7b/0x1850 vfs_write+0x645/0x780 ksys_write+0xf1/0x1e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd As 3db1de0e582c commit changed atomic write way which new a cow_inode for atomic write file, and also mark cow_inode as FI_ATOMIC_FILE. When f2fs_do_write_data_page write cow_inode will use cow_inode's cow_inode which is NULL. Then will trigger null-ptr-deref. To solve above issue, introduce FI_COW_FILE flag for COW inode. Fiexes: 3db1de0e582c("f2fs: change the current atomic write way")

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-50009 is a Linux kernel F2FS filesystem bug that can trigger a null pointer dereference during atomic write handling. The practical concern is availability: affected systems using F2FS may hit a kernel fault under the described write and garbage-collection path.

Executive priority

Treat as a targeted availability risk for F2FS-dependent Linux systems. It is not currently supported by provided evidence as internet-exploited or remotely exploitable, so prioritize patching based on F2FS usage and uptime requirements.

Technical view

The bug is in f2fs_get_dnode_of_data. A prior atomic-write change created a COW inode and marked it as FI_ATOMIC_FILE, causing writeback to reference a NULL cow_inode. The upstream resolution introduces FI_COW_FILE for COW inodes.

Likely exposure

Exposure is most likely on Linux systems using F2FS, particularly where atomic write behavior is exercised. The source does not identify affected distributions, cloud images, appliances, or remote attack surfaces.

Exploitation context

CISA KEV status is false in the source bundle, and no cited source states active exploitation. The report shows a KASAN null-ptr-deref during testing, not a public exploitation claim.

Researcher notes

Evidence is narrow and kernel-specific. The source describes a resolved null-ptr-deref in the F2FS atomic-write COW inode path and provides upstream stable commits, but no CVSS, CWE, exploitability analysis, or distro mapping.

Mitigation direction

  • Check vendor kernel guidance for CVE-2022-50009.
  • Update to a kernel package containing the referenced F2FS stable fixes.
  • Prioritize systems that mount or rely on F2FS volumes.
  • Restrict untrusted F2FS media or mounts where operationally feasible.
  • Monitor kernel logs for F2FS null pointer dereference crashes.

Validation and detection

  • Inventory Linux hosts and appliances using F2FS.
  • Map running kernel builds to vendor advisories or stable commits.
  • Review logs for f2fs_get_dnode_of_data or F2FS writeback crashes.
  • Confirm patched kernels include the FI_COW_FILE fix.
  • Avoid production reproduction; validate only in controlled lab systems.
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

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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

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  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

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Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux98e4da8ca301e062d79ae168c67e56f3c3de3ce4, 98e4da8ca301e062d79ae168c67e56f3c3de3ce4, 98e4da8ca301e062d79ae168c67e56f3c3de3ce4unaffected
LinuxLinux3.8, 0, 5.18.18, 5.19.4, 6.0affected
Weakness

CWE details

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