IM
IronMonkey Threat Research

CVE-2025-39691 HIGH

Published: 2025-09-05 | Last Modified: 2026-07-14 | Status: Modified

Description

In the Linux kernel, the following vulnerability has been resolved: fs/buffer: fix use-after-free when call bh_read() helper There's issue as follows: BUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110 Read of size 8 at addr ffffc9000168f7f8 by task swapper/3/0 CPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-862.14.0.6.x86_64 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Call Trace: <IRQ> dump_stack_lvl+0x55/0x70 print_address_description.constprop.0+0x2c/0x390 print_report+0xb4/0x270 kasan_report+0xb8/0xf0 end_buffer_read_sync+0xe3/0x110 end_bio_bh_io_sync+0x56/0x80 blk_update_request+0x30a/0x720 scsi_end_request+0x51/0x2b0 scsi_io_completion+0xe3/0x480 ? scsi_device_unbusy+0x11e/0x160 blk_complete_reqs+0x7b/0x90 handle_softirqs+0xef/0x370 irq_exit_rcu+0xa5/0xd0 sysvec_apic_timer_interrupt+0x6e/0x90 </IRQ> Above issue happens when do ntfs3 filesystem mount, issue may happens as follows: mount IRQ ntfs_fill_super read_cache_page do_read_cache_folio filemap_read_folio mpage_read_folio do_mpage_readpage ntfs_get_block_vbo bh_read submit_bh wait_on_buffer(bh); blk_complete_reqs scsi_io_completion scsi_end_request blk_update_request end_bio_bh_io_sync end_buffer_read_sync __end_buffer_read_notouch unlock_buffer wait_on_buffer(bh);--> return will return to caller put_bh --> trigger stack-out-of-bounds In the mpage_read_folio() function, the stack variable 'map_bh' is passed to ntfs_get_block_vbo(). Once unlock_buffer() unlocks and wait_on_buffer() returns to continue processing, the stack variable is likely to be reclaimed. Consequently, during the end_buffer_read_sync() process, calling put_bh() may result in stack overrun. If the bh is not allocated on the stack, it belongs to a folio. Freeing a buffer head which belongs to a folio is done by drop_buffers() which will fail to free buffers which are still locked. So it is safe to call put_bh() before __end_buffer_read_notouch().

CVSS Metrics

Base Score: 7.8 (HIGH)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack VectorLOCAL
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactHIGH
Integrity ImpactHIGH
Availability ImpactHIGH

Source: [email protected]

Type: Primary

Exploitability Score: 1.8

Impact Score: 5.9

Weaknesses

Source Type Description
[email protected] Primary
en CWE-416

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f4280> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f5980> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f5ec0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdd6a6540> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f5bc0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f7b00> Operating System
linux linux_kernel * <built-in method update of dict object at 0x702bdc9f7900> Operating System
linux linux_kernel 2.6.12 <built-in method update of dict object at 0x702bdc9f5000> Operating System
linux linux_kernel 2.6.12 <built-in method update of dict object at 0x702bdd6a51c0> Operating System
linux linux_kernel 2.6.12 <built-in method update of dict object at 0x702bdc9f5100> Operating System
linux linux_kernel 2.6.12 <built-in method update of dict object at 0x702bdc9f67c0> Operating System
linux linux_kernel 2.6.12 <built-in method update of dict object at 0x702bdc9f6e40> Operating System
linux linux_kernel 6.17 <built-in method update of dict object at 0x702bdd6a6c40> Operating System
linux linux_kernel 6.17 <built-in method update of dict object at 0x702bdc9f4f80> Operating System
debian debian_linux 11.0 <built-in method update of dict object at 0x702bdc9f6f40> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:*

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References

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