Linux Kernel up to 6.17-rc2 bh_read use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.7$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.17-rc2. Affected is the function bh_read. Executing a manipulation can lead to use after free. This vulnerability is tracked as CVE-2025-39691. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.17-rc2. It has been declared as critical. This vulnerability affects the function bh_read. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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().

The advisory is available at git.kernel.org. This vulnerability was named CVE-2025-39691 since 04/16/2025. The exploitation appears to be easy. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 02/09/2026).

The vulnerability scanner Nessus provides a plugin with the ID 261595 (Linux Distros Unpatched Vulnerability : CVE-2025-39691), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.297, 5.10.241, 5.15.190, 6.1.149, 6.6.103, 6.12.44, 6.16.4 or 6.17-rc3 eliminates this vulnerability. Applying the patch 70a09115da586bf662c3bae9c0c4a1b99251fad9/3169edb8945c295cf89120fc6b2c35cfe3ad4c9e/03b40bf5d0389ca23ae6857ee25789f0e0b47ce8/c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4/c5aa6ba1127307ab5dc3773eaf40d73a3423841f/042cf48ecf67f72c8b3846c7fac678f472712ff3/90b5193edb323fefbee0e4e5bc39ed89dcc37719/7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (261595) and CERT Bund (WID-SEC-2025-1988). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

  • Debian Linux
  • Google Cloud Platform
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • NetApp FAS
  • NetApp AFF
  • NetApp ActiveIQ Unified Manager
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Microsoft Azure
  • Dell Secure Connect Gateway
  • IBM QRadar SIEM
  • IBM Security Verify Access
  • Dell NetWorker

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
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Nessus ID: 261595
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39691

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.4.297/5.10.241/5.15.190/6.1.149/6.6.103/6.12.44/6.16.4/6.17-rc3
Patch: 70a09115da586bf662c3bae9c0c4a1b99251fad9/3169edb8945c295cf89120fc6b2c35cfe3ad4c9e/03b40bf5d0389ca23ae6857ee25789f0e0b47ce8/c58c6b532b7b69537cfd9ef701c7e37cdcf79dc4/c5aa6ba1127307ab5dc3773eaf40d73a3423841f/042cf48ecf67f72c8b3846c7fac678f472712ff3/90b5193edb323fefbee0e4e5bc39ed89dcc37719/7375f22495e7cd1c5b3b5af9dcc4f6dffe34ce49

Timelineinfo

04/16/2025 CVE reserved
09/05/2025 +142 days Advisory disclosed
09/05/2025 +0 days VulDB entry created
02/09/2026 +157 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39691 (🔒)
GCVE (CVE): GCVE-0-2025-39691
GCVE (VulDB): GCVE-100-322882
CERT Bund: WID-SEC-2025-1988 - Linux Kernel: Mehrere Schwachstellen erm&ouml;glichen Denial of Service

Entryinfo

Created: 09/05/2025 21:41
Updated: 02/09/2026 16:44
Changes: 09/05/2025 21:41 (58), 09/07/2025 20:30 (2), 11/06/2025 18:25 (7), 11/27/2025 16:56 (1), 01/03/2026 13:14 (1), 01/05/2026 12:08 (1), 01/09/2026 07:30 (12), 02/09/2026 16:44 (1)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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