Linux Kernel up to 6.6.139/6.12.87/6.18.29/7.0.6 f2fs f2fs_destroy_extent_node locking

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.6.139/6.12.87/6.18.29/7.0.6. Impacted is the function f2fs_destroy_extent_node of the component f2fs. The manipulation leads to locking. This vulnerability is documented as CVE-2026-46194. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.139/6.12.87/6.18.29/7.0.6 and classified as critical. This issue affects the function f2fs_destroy_extent_node of the component f2fs. The manipulation with an unknown input leads to a locking vulnerability. Using CWE to declare the problem leads to CWE-667. The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix node_cnt race between extent node destroy and writeback f2fs_destroy_extent_node() does not set FI_NO_EXTENT before clearing extent nodes. When called from f2fs_drop_inode() with I_SYNC set, concurrent kworker writeback can insert new extent nodes into the same extent tree, racing with the destroy and triggering f2fs_bug_on() in __destroy_extent_node(). The scenario is as follows: drop inode writeback - iput - f2fs_drop_inode // I_SYNC set - f2fs_destroy_extent_node - __destroy_extent_node - while (node_cnt) { write_lock(&et->lock) __free_extent_tree write_unlock(&et->lock) - __writeback_single_inode - f2fs_outplace_write_data - f2fs_update_read_extent_cache - __update_extent_tree_range // FI_NO_EXTENT not set, // insert new extent node } // node_cnt == 0, exit while - f2fs_bug_on(node_cnt) // node_cnt > 0 Additionally, __update_extent_tree_range() only checks FI_NO_EXTENT for EX_READ type, leaving EX_BLOCK_AGE updates completely unprotected. This patch set FI_NO_EXTENT under et->lock in __destroy_extent_node(), consistent with other callers (__update_extent_tree_range and __drop_extent_tree) and check FI_NO_EXTENT for both EX_READ and EX_BLOCK_AGE tree.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-46194 since 05/13/2026. The exploitation is known to be difficult. Technical details are known, but no exploit is available.

Upgrading to version 6.6.140, 6.12.88, 6.18.30, 7.0.7 or 7.1-rc1 eliminates this vulnerability. Applying the patch 42dd1c91f993431d0b399502479d00e6ad1bca71/ab1eaf9d5c99042f5b0243bf67a06283a4c0757f/b0e4395870eb3441ddc959f6710b5f6ca61aff26/0559a0e962aacbb47519e26ee663be04b72dcb92/ed78aeebef05212ef7dca93bd931e4eff67c113f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.6.139
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.12.64
• 6.12.65
• 6.12.66
• 6.12.67
• 6.12.68
• 6.12.69
• 6.12.70
• 6.12.71
• 6.12.72
• 6.12.73
• 6.12.74
• 6.12.75
• 6.12.76
• 6.12.77
• 6.12.78
• 6.12.79
• 6.12.80
• 6.12.81
• 6.12.82
• 6.12.83
• 6.12.84
• 6.12.85
• 6.12.86
• 6.12.87
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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