CVE-2023-54068
Use-After-Free in Linux f2fs Compression Causes Kernel BUG
Publication date: 2025-12-24
Last updated on: 2025-12-24
Assigner: kernel.org
Description
Description
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability in the Linux kernel's f2fs filesystem occurs because the function f2fs_write_raw_pages() does not properly wait for a page to finish writeback before attempting to write it again. This leads to a kernel BUG_ON() being triggered when files are written concurrently, as the same page is written back multiple times simultaneously. The issue was introduced by a previous commit that released all page locks without checking if the page was still in writeback state. The fix involves calling f2fs_wait_on_page_writeback() to ensure the page writeback completes before proceeding with another write.
How can this vulnerability impact me? :
This vulnerability can cause the Linux kernel to crash (kernel BUG) during concurrent file writes on the f2fs filesystem, leading to system instability or downtime. Such crashes can result in data loss or corruption and disrupt normal system operations.
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 BUG messages related to f2fs writeback errors, specifically kernel BUG at mm/filemap.c:1619. You can check the kernel logs for such BUG_ON() triggers using commands like 'dmesg | grep BUG' or 'journalctl -k | grep BUG'. Additionally, monitoring for system crashes or kernel panics during concurrent file writes on f2fs file systems may indicate this issue.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed, as the issue is resolved by calling f2fs_wait_on_page_writeback() in f2fs_write_raw_pages(). Until an update is applied, avoid concurrent writes to files on f2fs file systems to prevent triggering the BUG_ON().