CVE-2023-54151 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
f2fs: Fix system crash due to lack of free space in LFS
When f2fs tries to checkpoint during foreground gc in LFS mode, system crash occurs due to lack of free space if the amount of dirty node and dentry pages generated by data migration exceeds free space. The reproduction sequence is as follows.
- 20GiB capacity block device (null_blk) - format and mount with LFS mode - create a file and write 20,000MiB - 4k random write on full range of the file
RIP: 0010:new_curseg+0x48a/0x510 [f2fs]
Code: 55 e7 f5 89 c0 48 0f af c3 48 8b 5d c0 48 c1 e8 20 83 c0 01 89 43 6c 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc <0f> 0b f0 41 80 4f 48 04 45 85 f6 0f 84 ba fd ff ff e9 ef fe ff ff RSP: 0018:ffff977bc397b218 EFLAGS: 00010246 RAX: 00000000000027b9 RBX: 0000000000000000 RCX: 00000000000027c0 RDX: 0000000000000000 RSI: 00000000000027b9 RDI: ffff8c25ab4e74f8 RBP: ffff977bc397b268 R08: 00000000000027b9 R09: ffff8c29e4a34b40 R10: 0000000000000001 R11: ffff977bc397b0d8 R12: 0000000000000000 R13: ffff8c25b4dd81a0 R14: 0000000000000000 R15: ffff8c2f667f9000 FS: 0000000000000000(0000) GS:ffff8c344ec80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00055d000 CR3: 0000000e30810003 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> allocate_segment_by_default+0x9c/0x110 [f2fs]
f2fs_allocate_data_block+0x243/0xa30 [f2fs]
? __mod_lruvec_page_state+0xa0/0x150 do_write_page+0x80/0x160 [f2fs]
f2fs_do_write_node_page+0x32/0x50 [f2fs]
__write_node_page+0x339/0x730 [f2fs]
f2fs_sync_node_pages+0x5a6/0x780 [f2fs]
block_operations+0x257/0x340 [f2fs]
f2fs_write_checkpoint+0x102/0x1050 [f2fs]
f2fs_gc+0x27c/0x630 [f2fs]
? folio_mark_dirty+0x36/0x70 f2fs_balance_fs+0x16f/0x180 [f2fs]
This patch adds checking whether free sections are enough before checkpoint during gc.
[Jaegeuk Kim: code clean-up]
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/03/2026
The vulnerability identified as CVE-2023-54151 represents a critical system crash condition within the Linux kernel's f2fs filesystem implementation, specifically when operating in Log-Structured File System (LFS) mode. This flaw manifests during foreground garbage collection operations when the filesystem attempts to create checkpoints, leading to a complete system crash due to insufficient free space allocation. The vulnerability operates through a specific sequence of operations that stress the filesystem's memory management and allocation mechanisms, ultimately causing a kernel panic when the system attempts to allocate memory segments during checkpoint creation.
The technical root cause of this vulnerability stems from inadequate space management checks within the f2fs filesystem's garbage collection process. When data migration occurs and generates a substantial amount of dirty node and dentry pages, the system fails to properly verify whether sufficient free space exists before attempting to checkpoint during foreground garbage collection. This condition creates a scenario where the kernel's memory allocation functions attempt to access memory regions that are either already allocated or unavailable, resulting in a segmentation fault and subsequent system crash. The crash occurs at the new_curseg function within the f2fs module, indicating a failure in segment allocation during the checkpointing process.
The operational impact of this vulnerability is severe as it can lead to complete system instability and data loss. When a system running f2fs in LFS mode encounters this condition, particularly during high I/O operations involving large files, the entire system becomes unresponsive and crashes. The call trace reveals a clear path through the filesystem's memory management subsystem, showing how the issue propagates from the initial checkpoint attempt through various memory allocation and page management functions before ultimately failing during segment allocation. This vulnerability affects systems where f2fs is used with LFS mode and experiences heavy write workloads, making it particularly dangerous in production environments.
The mitigation strategy for this vulnerability involves implementing proper space availability checks before initiating checkpoint operations during garbage collection. The patch addresses this by adding validation logic that ensures sufficient free sections exist before proceeding with checkpoint creation. This approach aligns with security best practices for resource management and prevents the kernel from attempting operations that would result in memory allocation failures. From a cybersecurity perspective, this vulnerability demonstrates the importance of proper resource boundary checking in kernel modules and the potential for denial-of-service conditions in storage subsystems. The fix specifically addresses the issue by preventing checkpoint operations when free space is insufficient, thereby maintaining system stability and preventing the kernel panic that occurs during memory allocation failures.
This vulnerability can be classified under CWE-129 as an Improper Input Validation, specifically related to insufficient validation of resource availability. The flaw also relates to ATT&CK technique T1499.001 for Network Denial of Service, as it can cause complete system crashes. The vulnerability highlights the critical importance of proper resource management in kernel-level filesystem implementations and demonstrates how seemingly minor oversights in space allocation checks can result in catastrophic system failures. The fix ensures that the filesystem maintains consistent state and prevents the kernel from entering an unrecoverable state during memory allocation operations, thereby preserving system integrity and availability.