CVE-2025-38194
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: jffs2: check that raw node were preallocated before writing summary Syzkaller detected a kernel bug in jffs2_link_node_ref, caused by fault injection in jffs2_prealloc_raw_node_refs. jffs2_sum_write_sumnode doesn't check return value of jffs2_prealloc_raw_node_refs and simply lets any error propagate into jffs2_sum_write_data, which eventually calls jffs2_link_node_ref in order to link the summary to an expectedly allocated node. kernel BUG at fs/jffs2/nodelist.c:592! invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 1 PID: 31277 Comm: syz-executor.7 Not tainted 6.1.128-syzkaller-00139-ge10f83ca10a1 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:jffs2_link_node_ref+0x570/0x690 fs/jffs2/nodelist.c:592 Call Trace: <TASK> jffs2_sum_write_data fs/jffs2/summary.c:841 [inline] jffs2_sum_write_sumnode+0xd1a/0x1da0 fs/jffs2/summary.c:874 jffs2_do_reserve_space+0xa18/0xd60 fs/jffs2/nodemgmt.c:388 jffs2_reserve_space+0x55f/0xaa0 fs/jffs2/nodemgmt.c:197 jffs2_write_inode_range+0x246/0xb50 fs/jffs2/write.c:362 jffs2_write_end+0x726/0x15d0 fs/jffs2/file.c:301 generic_perform_write+0x314/0x5d0 mm/filemap.c:3856 __generic_file_write_iter+0x2ae/0x4d0 mm/filemap.c:3973 generic_file_write_iter+0xe3/0x350 mm/filemap.c:4005 call_write_iter include/linux/fs.h:2265 [inline] do_iter_readv_writev+0x20f/0x3c0 fs/read_write.c:735 do_iter_write+0x186/0x710 fs/read_write.c:861 vfs_iter_write+0x70/0xa0 fs/read_write.c:902 iter_file_splice_write+0x73b/0xc90 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0x10c/0x170 fs/splice.c:950 splice_direct_to_actor+0x337/0xa10 fs/splice.c:896 do_splice_direct+0x1a9/0x280 fs/splice.c:1002 do_sendfile+0xb13/0x12c0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x1cf/0x210 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 Fix this issue by checking return value of jffs2_prealloc_raw_node_refs before calling jffs2_sum_write_data. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
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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-2025-38194
Affected Vendors & Products
Showing 8 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 2.6.18 (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
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CWE ID Description
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a bug in the Linux kernel's JFFS2 filesystem code. Specifically, the function jffs2_sum_write_sumnode does not check the return value of jffs2_prealloc_raw_node_refs, which can lead to errors propagating into subsequent functions. This causes the kernel to attempt to link a summary node to a raw node that was not properly preallocated, resulting in a kernel bug and invalid opcode error. The issue was detected by Syzkaller through fault injection and is fixed by adding a check on the return value before proceeding.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to crash or behave unpredictably due to a kernel bug triggered when writing to the JFFS2 filesystem. This can lead to system instability, potential data loss, or denial of service if the kernel encounters the invalid opcode error during filesystem operations.


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