CVE-2025-38626
BaseFortify
Publication date: 2025-08-22
Last updated on: 2026-03-25
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | From 5.15.160 (inc) to 5.16 (inc) |
| linux | linux_kernel | From 5.15.160 (inc) to 5.16 (inc) |
| linux | linux_kernel | From 5.15.160 (inc) to 5.16 (inc) |
| linux | linux_kernel | From 5.15.160 (inc) to 5.16 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-NVD-CWE-noinfo |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is in the Linux kernel's f2fs filesystem when mounted with the 'mode=lfs' option. The issue occurs in the f2fs_map_blocks() function, which may cause a system panic (kernel BUG) due to improper handling of foreground garbage collection (gc). Specifically, foreground gc is only triggered after allocating a physical block, but under certain conditions with multiple threads writing data in parallel, aggressive block allocation can lead to running out of space and a kernel panic. The fix involves allowing foreground gc to be triggered before block allocation to prevent this panic.
How can this vulnerability impact me? :
This vulnerability can cause a system panic (kernel crash) when using the f2fs filesystem with the 'mode=lfs' mount option under heavy parallel write loads. This can lead to system instability, potential data loss, and downtime as the kernel crashes unexpectedly.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring for kernel panic messages related to f2fs filesystem operations, specifically errors mentioning 'kernel BUG at fs/f2fs/segment.c:2835' or call traces involving f2fs_map_blocks and new_curseg. You can check the system logs using commands like 'dmesg | grep f2fs' or 'journalctl -k | grep f2fs' to look for such panic messages. Additionally, monitoring for system panics or crashes during heavy write operations using aio/dio/bufio methods on f2fs mounted with 'mode=lfs' can help detect the issue.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include avoiding mounting f2fs filesystems with the 'mode=lfs' option until the kernel is updated with the fix. Reducing or stopping parallel write operations using aio/dio/bufio methods on f2fs filesystems can also help prevent triggering the bug. Applying the kernel update that includes the fix to trigger foreground garbage collection prior to block allocation in f2fs_map_blocks is the definitive solution.