CVE-2025-38222
Analyzed Analyzed - Analysis Complete
BaseFortify

Publication date: 2025-07-04

Last updated on: 2025-12-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ext4: inline: fix len overflow in ext4_prepare_inline_data When running the following code on an ext4 filesystem with inline_data feature enabled, it will lead to the bug below. fd = open("file1", O_RDWR | O_CREAT | O_TRUNC, 0666); ftruncate(fd, 30); pwrite(fd, "a", 1, (1UL << 40) + 5UL); That happens because write_begin will succeed as when ext4_generic_write_inline_data calls ext4_prepare_inline_data, pos + len will be truncated, leading to ext4_prepare_inline_data parameter to be 6 instead of 0x10000000006. Then, later when write_end is called, we hit: BUG_ON(pos + len > EXT4_I(inode)->i_inline_size); at ext4_write_inline_data. Fix it by using a loff_t type for the len parameter in ext4_prepare_inline_data instead of an unsigned int. [ 44.545164] ------------[ cut here ]------------ [ 44.545530] kernel BUG at fs/ext4/inline.c:240! [ 44.545834] Oops: invalid opcode: 0000 [#1] SMP NOPTI [ 44.546172] CPU: 3 UID: 0 PID: 343 Comm: test Not tainted 6.15.0-rc2-00003-g9080916f4863 #45 PREEMPT(full) 112853fcebfdb93254270a7959841d2c6aa2c8bb [ 44.546523] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 44.546523] RIP: 0010:ext4_write_inline_data+0xfe/0x100 [ 44.546523] Code: 3c 0e 48 83 c7 48 48 89 de 5b 41 5c 41 5d 41 5e 41 5f 5d e9 e4 fa 43 01 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 0f 0b <0f> 0b 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 20 49 [ 44.546523] RSP: 0018:ffffb342008b79a8 EFLAGS: 00010216 [ 44.546523] RAX: 0000000000000001 RBX: ffff9329c579c000 RCX: 0000010000000006 [ 44.546523] RDX: 000000000000003c RSI: ffffb342008b79f0 RDI: ffff9329c158e738 [ 44.546523] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 [ 44.546523] R10: 00007ffffffff000 R11: ffffffff9bd0d910 R12: 0000006210000000 [ 44.546523] R13: fffffc7e4015e700 R14: 0000010000000005 R15: ffff9329c158e738 [ 44.546523] FS: 00007f4299934740(0000) GS:ffff932a60179000(0000) knlGS:0000000000000000 [ 44.546523] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 44.546523] CR2: 00007f4299a1ec90 CR3: 0000000002886002 CR4: 0000000000770eb0 [ 44.546523] PKRU: 55555554 [ 44.546523] Call Trace: [ 44.546523] <TASK> [ 44.546523] ext4_write_inline_data_end+0x126/0x2d0 [ 44.546523] generic_perform_write+0x17e/0x270 [ 44.546523] ext4_buffered_write_iter+0xc8/0x170 [ 44.546523] vfs_write+0x2be/0x3e0 [ 44.546523] __x64_sys_pwrite64+0x6d/0xc0 [ 44.546523] do_syscall_64+0x6a/0xf0 [ 44.546523] ? __wake_up+0x89/0xb0 [ 44.546523] ? xas_find+0x72/0x1c0 [ 44.546523] ? next_uptodate_folio+0x317/0x330 [ 44.546523] ? set_pte_range+0x1a6/0x270 [ 44.546523] ? filemap_map_pages+0x6ee/0x840 [ 44.546523] ? ext4_setattr+0x2fa/0x750 [ 44.546523] ? do_pte_missing+0x128/0xf70 [ 44.546523] ? security_inode_post_setattr+0x3e/0xd0 [ 44.546523] ? ___pte_offset_map+0x19/0x100 [ 44.546523] ? handle_mm_fault+0x721/0xa10 [ 44.546523] ? do_user_addr_fault+0x197/0x730 [ 44.546523] ? do_syscall_64+0x76/0xf0 [ 44.546523] ? arch_exit_to_user_mode_prepare+0x1e/0x60 [ 44.546523] ? irqentry_exit_to_user_mode+0x79/0x90 [ 44.546523] entry_SYSCALL_64_after_hwframe+0x55/0x5d [ 44.546523] RIP: 0033:0x7f42999c6687 [ 44.546523] Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff [ 44.546523] RSP: 002b:00007ffeae4a7930 EFLAGS: 00000202 ORIG_RAX: 0000000000000012 [ 44.546523] RAX: ffffffffffffffda RBX: 00007f4299934740 RCX: 00007f42999c6687 [ 44.546523] RDX: 0000000000000001 RSI: 000055ea6149200f RDI: 0000000000000003 [ 44.546523] RBP: 00007ffeae4a79a0 R08: 0000000000000000 R09: 0000000000000000 [ 44.546523] R10: 0000010000000005 R11: 0000000000000202 R12: 0000 ---truncated---
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Meta Information
Published
2025-07-04
Last Modified
2025-12-18
Generated
2026-05-07
AI Q&A
2025-07-04
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38222
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 3.8 (inc) to 5.4.295 (exc)
linux linux_kernel From 5.5 (inc) to 5.10.239 (exc)
linux linux_kernel From 5.11 (inc) to 5.15.186 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.142 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.95 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.35 (exc)
linux linux_kernel From 6.13 (inc) to 6.15.4 (exc)
debian debian_linux 11.0
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a bug in the Linux kernel's ext4 filesystem when the inline_data feature is enabled. It occurs due to an integer overflow in the ext4_prepare_inline_data function, where the length parameter is truncated improperly. This causes a mismatch in expected data sizes during write operations, leading to a kernel BUG and potential system crash when writing data at a very large offset.


How can this vulnerability impact me? :

This vulnerability can cause a kernel crash (BUG) when performing certain write operations on an ext4 filesystem with inline_data enabled. This can lead to system instability or denial of service, potentially interrupting normal operations and causing data loss or corruption.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability manifests as a kernel BUG triggered by specific writes to an ext4 filesystem with the inline_data feature enabled. Detection involves monitoring kernel logs for BUG_ON messages related to ext4_write_inline_data, especially after running suspicious write operations. You can check kernel logs using commands like 'dmesg | grep ext4_write_inline_data' or 'journalctl -k | grep ext4_write_inline_data'. Additionally, testing the vulnerable code snippet on a test system with an ext4 filesystem with inline_data enabled can reproduce the bug.


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 changing the len parameter type in ext4_prepare_inline_data. If updating is not immediately possible, avoid running untrusted code that performs large offset writes on ext4 filesystems with inline_data enabled. Monitoring and restricting access to systems with ext4 inline_data enabled can also reduce risk.


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