CVE-2026-46194
Race Condition in Linux Kernel F2FS Extent Node Handling
Publication date: 2026-05-28
Last updated on: 2026-05-28
Assigner: kernel.org
Description
Description
CVSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux_kernel | f2fs | * |
| 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 exists in the Linux kernel's f2fs filesystem, specifically involving a race condition between destroying extent nodes and concurrent writeback operations.
The function f2fs_destroy_extent_node() does not set a flag (FI_NO_EXTENT) before clearing extent nodes. When this function is called from f2fs_drop_inode() with the I_SYNC flag set, a concurrent kernel worker performing writeback can insert new extent nodes into the same extent tree. This causes a race condition that triggers a kernel bug check (f2fs_bug_on()) because the node count is unexpectedly greater than zero during destruction.
Additionally, the function __update_extent_tree_range() only checks the FI_NO_EXTENT flag for one type of extent update (EX_READ), leaving another type (EX_BLOCK_AGE) unprotected, which can also contribute to the issue.
The fix involves setting the FI_NO_EXTENT flag properly under a lock during extent node destruction and ensuring the flag is checked for both EX_READ and EX_BLOCK_AGE updates to prevent this race condition.
How can this vulnerability impact me? :
This vulnerability can cause a race condition in the f2fs filesystem leading to a kernel bug check (f2fs_bug_on()), which may result in system instability or crashes.
Such instability can lead to data loss or corruption, especially in systems relying on the f2fs filesystem for storage.
Because the issue occurs during inode drop and writeback operations, it may affect system reliability and availability.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability has been resolved by a patch in the Linux kernel that fixes a race condition in the f2fs filesystem code related to extent node destruction and writeback.
To mitigate this vulnerability immediately, you should update your Linux kernel to a version that includes this fix.
No specific workaround or configuration change is described in the provided information.