Linux Kernel up to 6.17-rc5 kernel/sched/core.c ocfs2_fiemap memory corruption

CVSS Meta Temp Score
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CTI Interest Score
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6.6$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.1.152/6.6.106/6.12.47/6.16.7/6.17-rc5. This impacts the function ocfs2_fiemap of the file kernel/sched/core.c. This manipulation causes memory corruption. The identification of this vulnerability is CVE-2025-39885. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.152/6.6.106/6.12.47/6.16.7/6.17-rc5. It has been declared as critical. Affected by this vulnerability is the function ocfs2_fiemap of the file kernel/sched/core.c. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix recursive semaphore deadlock in fiemap call syzbot detected a OCFS2 hang due to a recursive semaphore on a FS_IOC_FIEMAP of the extent list on a specially crafted mmap file. context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7115 rwsem_down_write_slowpath+0x872/0xfe0 kernel/locking/rwsem.c:1185 __down_write_common kernel/locking/rwsem.c:1317 [inline] __down_write kernel/locking/rwsem.c:1326 [inline] down_write+0x1ab/0x1f0 kernel/locking/rwsem.c:1591 ocfs2_page_mkwrite+0x2ff/0xc40 fs/ocfs2/mmap.c:142 do_page_mkwrite+0x14d/0x310 mm/memory.c:3361 wp_page_shared mm/memory.c:3762 [inline] do_wp_page+0x268d/0x5800 mm/memory.c:3981 handle_pte_fault mm/memory.c:6068 [inline] __handle_mm_fault+0x1033/0x5440 mm/memory.c:6195 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364 do_user_addr_fault+0x764/0x1390 arch/x86/mm/fault.c:1387 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline] RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:197 [inline] RIP: 0010:_copy_to_user+0x85/0xb0 lib/usercopy.c:26 Code: e8 00 bc f7 fc 4d 39 fc 72 3d 4d 39 ec 77 38 e8 91 b9 f7 fc 4c 89 f7 89 de e8 47 25 5b fd 0f 01 cb 4c 89 ff 48 89 d9 4c 89 f6 <f3> a4 0f 1f 00 48 89 cb 0f 01 ca 48 89 d8 5b 41 5c 41 5d 41 5e 41 RSP: 0018:ffffc9000403f950 EFLAGS: 00050256 RAX: ffffffff84c7f101 RBX: 0000000000000038 RCX: 0000000000000038 RDX: 0000000000000000 RSI: ffffc9000403f9e0 RDI: 0000200000000060 RBP: ffffc9000403fa90 R08: ffffc9000403fa17 R09: 1ffff92000807f42 R10: dffffc0000000000 R11: fffff52000807f43 R12: 0000200000000098 R13: 00007ffffffff000 R14: ffffc9000403f9e0 R15: 0000200000000060 copy_to_user include/linux/uaccess.h:225 [inline] fiemap_fill_next_extent+0x1c0/0x390 fs/ioctl.c:145 ocfs2_fiemap+0x888/0xc90 fs/ocfs2/extent_map.c:806 ioctl_fiemap fs/ioctl.c:220 [inline] do_vfs_ioctl+0x1173/0x1430 fs/ioctl.c:532 __do_sys_ioctl fs/ioctl.c:596 [inline] __se_sys_ioctl+0x82/0x170 fs/ioctl.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5f13850fd9 RSP: 002b:00007ffe3b3518b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000200000000000 RCX: 00007f5f13850fd9 RDX: 0000200000000040 RSI: 00000000c020660b RDI: 0000000000000004 RBP: 6165627472616568 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe3b3518f0 R13: 00007ffe3b351b18 R14: 431bde82d7b634db R15: 00007f5f1389a03b ocfs2_fiemap() takes a read lock of the ip_alloc_sem semaphore (since v2.6.22-527-g7307de80510a) and calls fiemap_fill_next_extent() to read the extent list of this running mmap executable. The user supplied buffer to hold the fiemap information page faults calling ocfs2_page_mkwrite() which will take a write lock (since v2.6.27-38-g00dc417fa3e7) of the same semaphore. This recursive semaphore will hold filesystem locks and causes a hang of the fileystem. The ip_alloc_sem protects the inode extent list and size. Release the read semphore before calling fiemap_fill_next_extent() in ocfs2_fiemap() and ocfs2_fiemap_inline(). This does an unnecessary semaphore lock/unlock on the last extent but simplifies the error path.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2025-39885 since 04/16/2025. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 02/16/2026).

The vulnerability scanner Nessus provides a plugin with the ID 265862 (Linux Distros Unpatched Vulnerability : CVE-2025-39885), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.153, 6.6.107, 6.12.48, 6.16.8 or 6.17-rc6 eliminates this vulnerability. Applying the patch 36054554772f95d090eb45793faf6aa3c0254b02/0709bc11b942870fc0a7be150e42aea42321093a/1d3c96547ee2ddeaddf8f19a3ef99ea06cc8115e/9efcb7a8b97310efed995397941a292cf89fa94f/04100f775c2ea501927f508f17ad824ad1f23c8d 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 (265862) and CERT Bund (WID-SEC-2025-2107). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Dell Secure Connect Gateway
  • IBM QRadar SIEM
  • Dell NetWorker

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.6

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

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 265862
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39885

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.153/6.6.107/6.12.48/6.16.8/6.17-rc6
Patch: 36054554772f95d090eb45793faf6aa3c0254b02/0709bc11b942870fc0a7be150e42aea42321093a/1d3c96547ee2ddeaddf8f19a3ef99ea06cc8115e/9efcb7a8b97310efed995397941a292cf89fa94f/04100f775c2ea501927f508f17ad824ad1f23c8d

Timelineinfo

04/16/2025 CVE reserved
09/23/2025 +160 days Advisory disclosed
09/23/2025 +0 days VulDB entry created
02/16/2026 +146 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39885 (🔒)
GCVE (CVE): GCVE-0-2025-39885
GCVE (VulDB): GCVE-100-325609
CERT Bund: WID-SEC-2025-2107 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 09/23/2025 08:39
Updated: 02/16/2026 09:39
Changes: 09/23/2025 08:39 (59), 09/28/2025 21:40 (2), 12/02/2025 05:07 (7), 01/12/2026 09:56 (1), 01/16/2026 20:50 (12), 02/09/2026 08:19 (1), 02/16/2026 09:39 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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