CVE-2025-68337
Unknown Unknown - Not Provided
Kernel BUG Trigger in Linux jbd2 Journal on Filesystem Corruption

Publication date: 2025-12-22

Last updated on: 2025-12-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: jbd2: avoid bug_on in jbd2_journal_get_create_access() when file system corrupted There's issue when file system corrupted: ------------[ cut here ]------------ kernel BUG at fs/jbd2/transaction.c:1289! Oops: invalid opcode: 0000 [#1] SMP KASAN PTI CPU: 5 UID: 0 PID: 2031 Comm: mkdir Not tainted 6.18.0-rc1-next RIP: 0010:jbd2_journal_get_create_access+0x3b6/0x4d0 RSP: 0018:ffff888117aafa30 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff88811a86b000 RCX: ffffffff89a63534 RDX: 1ffff110200ec602 RSI: 0000000000000004 RDI: ffff888100763010 RBP: ffff888100763000 R08: 0000000000000001 R09: ffff888100763028 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88812c432000 R14: ffff88812c608000 R15: ffff888120bfc000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f91d6970c99 CR3: 00000001159c4000 CR4: 00000000000006f0 Call Trace: <TASK> __ext4_journal_get_create_access+0x42/0x170 ext4_getblk+0x319/0x6f0 ext4_bread+0x11/0x100 ext4_append+0x1e6/0x4a0 ext4_init_new_dir+0x145/0x1d0 ext4_mkdir+0x326/0x920 vfs_mkdir+0x45c/0x740 do_mkdirat+0x234/0x2f0 __x64_sys_mkdir+0xd6/0x120 do_syscall_64+0x5f/0xfa0 entry_SYSCALL_64_after_hwframe+0x76/0x7e The above issue occurs with us in errors=continue mode when accompanied by storage failures. There have been many inconsistencies in the file system data. In the case of file system data inconsistency, for example, if the block bitmap of a referenced block is not set, it can lead to the situation where a block being committed is allocated and used again. As a result, the following condition will not be satisfied then trigger BUG_ON. Of course, it is entirely possible to construct a problematic image that can trigger this BUG_ON through specific operations. In fact, I have constructed such an image and easily reproduced this issue. Therefore, J_ASSERT() holds true only under ideal conditions, but it may not necessarily be satisfied in exceptional scenarios. Using J_ASSERT() directly in abnormal situations would cause the system to crash, which is clearly not what we want. So here we directly trigger a JBD abort instead of immediately invoking BUG_ON.
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Meta Information
Published
2025-12-22
Last Modified
2025-12-22
Generated
2026-05-07
AI Q&A
2025-12-23
EPSS Evaluated
2026-05-05
NVD
CVE-2025-68337
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.18.0-rc1-next
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's jbd2 journaling system, specifically in the function jbd2_journal_get_create_access(). When the file system is corrupted, certain inconsistencies in file system data (such as an unset block bitmap for a referenced block) can cause the system to trigger a BUG_ON condition, leading to a kernel crash. The issue arises because the code uses J_ASSERT() which assumes ideal conditions, but in corrupted or abnormal scenarios, this assumption fails and causes a crash. The fix avoids triggering BUG_ON and instead triggers a JBD abort to handle the error more gracefully.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash (kernel BUG) when the file system is corrupted and certain error conditions occur. This can lead to system instability, unexpected reboots, or data loss due to the kernel panic triggered by the BUG_ON condition in the journaling code.


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