{"id":"CVE-2025-39691","title":"fs/buffer: fix use-after-free when call bh_read() helper","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nfs/buffer: fix use-after-free when call bh_read() helper\n\nThere's issue as follows:\nBUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110\nRead of size 8 at…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 70a09115da586bf662c3bae9c0c4a1b99251fad9","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3169edb8945c295cf89120fc6b2c35cfe3ad4c9e","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 03b40bf5d0389ca23ae6857ee25789f0e0b47ce8","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c5aa6ba1127307ab5dc3773eaf40d73a3423841f","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 042cf48ecf67f72c8b3846c7fac678f472712ff3","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 90b5193edb323fefbee0e4e5bc39ed89dcc37719","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49","Linux 2.6.12"],"published":"2025-09-05","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:42:07.554Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39691","references":[{"url":"https://git.kernel.org/stable/c/70a09115da586bf662c3bae9c0c4a1b99251fad9"},{"url":"https://git.kernel.org/stable/c/3169edb8945c295cf89120fc6b2c35cfe3ad4c9e"},{"url":"https://git.kernel.org/stable/c/03b40bf5d0389ca23ae6857ee25789f0e0b47ce8"},{"url":"https://git.kernel.org/stable/c/c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4"},{"url":"https://git.kernel.org/stable/c/c5aa6ba1127307ab5dc3773eaf40d73a3423841f"},{"url":"https://git.kernel.org/stable/c/042cf48ecf67f72c8b3846c7fac678f472712ff3"},{"url":"https://git.kernel.org/stable/c/90b5193edb323fefbee0e4e5bc39ed89dcc37719"},{"url":"https://git.kernel.org/stable/c/7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49"}],"tags":["cve.org"],"epss":0.00175,"epssPercentile":0.07307,"ingestedAt":"2026-09-08T15:33:26.997Z","slug":"CVE-2025-39691","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nfs/buffer: fix use-after-free when call bh_read() helper\n\nThere's issue as follows:\nBUG: KASAN: stack-out-of-bounds in end_buffer_read_sync+0xe3/0x110\nRead of size 8 at addr ffffc9000168f7f8 by task swapper/3/0\nCPU: 3 UID: 0 PID: 0 Comm: swapper/3 Not tainted 6.16.0-862.14.0.6.x86_64\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996)\nCall Trace:\n <IRQ>\n dump_stack_lvl+0x55/0x70\n print_address_description.constprop.0+0x2c/0x390\n print_report+0xb4/0x270\n kasan_report+0xb8/0xf0\n end_buffer_read_sync+0xe3/0x110\n end_bio_bh_io_sync+0x56/0x80\n blk_update_request+0x30a/0x720\n scsi_end_request+0x51/0x2b0\n scsi_io_completion+0xe3/0x480\n ? scsi_device_unbusy+0x11e/0x160\n blk_complete_reqs+0x7b/0x90\n handle_softirqs+0xef/0x370\n irq_exit_rcu+0xa5/0xd0\n sysvec_apic_timer_interrupt+0x6e/0x90\n </IRQ>\n\n Above issue happens when do ntfs3 filesystem mount, issue may happens\n as follows:\n           mount                            IRQ\nntfs_fill_super\n  read_cache_page\n    do_read_cache_folio\n      filemap_read_folio\n        mpage_read_folio\n\t do_mpage_readpage\n\t  ntfs_get_block_vbo\n\t   bh_read\n\t     submit_bh\n\t     wait_on_buffer(bh);\n\t                            blk_complete_reqs\n\t\t\t\t     scsi_io_completion\n\t\t\t\t      scsi_end_request\n\t\t\t\t       blk_update_request\n\t\t\t\t        end_bio_bh_io_sync\n\t\t\t\t\t end_buffer_read_sync\n\t\t\t\t\t  __end_buffer_read_notouch\n\t\t\t\t\t   unlock_buffer\n\n            wait_on_buffer(bh);--> return will return to caller\n\n\t\t\t\t\t  put_bh\n\t\t\t\t\t    --> trigger stack-out-of-bounds\nIn the mpage_read_folio() function, the stack variable 'map_bh' is\npassed to ntfs_get_block_vbo(). Once unlock_buffer() unlocks and\nwait_on_buffer() returns to continue processing, the stack variable\nis likely to be reclaimed. Consequently, during the end_buffer_read_sync()\nprocess, calling put_bh() may result in stack overrun.\n\nIf the bh is not allocated on the stack, it belongs to a folio.  Freeing\na buffer head which belongs to a folio is done by drop_buffers() which\nwill fail to free buffers which are still locked.  So it is safe to call\nput_bh() before __end_buffer_read_notouch().\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 70a09115da586bf662c3bae9c0c4a1b99251fad9`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3169edb8945c295cf89120fc6b2c35cfe3ad4c9e`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 03b40bf5d0389ca23ae6857ee25789f0e0b47ce8`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < c5aa6ba1127307ab5dc3773eaf40d73a3423841f`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 042cf48ecf67f72c8b3846c7fac678f472712ff3`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 90b5193edb323fefbee0e4e5bc39ed89dcc37719`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}