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CVE-2025-21642— mptcp: sysctl: sched: avoid using current->nsproxy

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于空指针取消引用。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.25% · P16

Possible ATT&CK Techniques 1 AI

T1053 · Scheduled Task/Job

Affected Version Matrix 11

VendorProduct Version RangeStatus
Linux Linux daad878a509d69da1761106cb48c091dfe9d522d< c0e394fd6b887e84da17e38aaa6c1c104f9c86c2 affected
6963c508fd7ab66ae0b7ae3db9a62ca6267f1ae8< 6035702381c35a8f16757332381e58b348a9eaf9 affected
6963c508fd7ab66ae0b7ae3db9a62ca6267f1ae8< d38e26e36206ae3d544d496513212ae931d1da0a affected
1e444f5f2a07844354ad767b44ed0a713211e26d affected
6.6.31< 6.6.72 affected
6.8.10< 6.9 affected
6.9 affected
< 6.9 unaffected
… +3 more rows
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I. Basic Information for CVE-2025-21642

Vulnerability Information
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Vulnerability Title
mptcp: sysctl: sched: avoid using current->nsproxy
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: mptcp: sysctl: sched: avoid using current->nsproxy Using the 'net' structure via 'current' is not recommended for different reasons. First, if the goal is to use it to read or write per-netns data, this is inconsistent with how the "generic" sysctl entries are doing: directly by only using pointers set to the table entry, e.g. table->data. Linked to that, the per-netns data should always be obtained from the table linked to the netns it had been created for, which may not coincide with the reader's or writer's netns. Another reason is that access to current->nsproxy->netns can oops if attempted when current->nsproxy had been dropped when the current task is exiting. This is what syzbot found, when using acct(2): Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] CPU: 1 UID: 0 PID: 5924 Comm: syz-executor Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:proc_scheduler+0xc6/0x3c0 net/mptcp/ctrl.c:125 Code: 03 42 80 3c 38 00 0f 85 fe 02 00 00 4d 8b a4 24 08 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d 7c 24 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 cc 02 00 00 4d 8b 7c 24 28 48 8d 84 24 c8 00 00 RSP: 0018:ffffc900034774e8 EFLAGS: 00010206 RAX: dffffc0000000000 RBX: 1ffff9200068ee9e RCX: ffffc90003477620 RDX: 0000000000000005 RSI: ffffffff8b08f91e RDI: 0000000000000028 RBP: 0000000000000001 R08: ffffc90003477710 R09: 0000000000000040 R10: 0000000000000040 R11: 00000000726f7475 R12: 0000000000000000 R13: ffffc90003477620 R14: ffffc90003477710 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee3cd452d8 CR3: 000000007d116000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> proc_sys_call_handler+0x403/0x5d0 fs/proc/proc_sysctl.c:601 __kernel_write_iter+0x318/0xa80 fs/read_write.c:612 __kernel_write+0xf6/0x140 fs/read_write.c:632 do_acct_process+0xcb0/0x14a0 kernel/acct.c:539 acct_pin_kill+0x2d/0x100 kernel/acct.c:192 pin_kill+0x194/0x7c0 fs/fs_pin.c:44 mnt_pin_kill+0x61/0x1e0 fs/fs_pin.c:81 cleanup_mnt+0x3ac/0x450 fs/namespace.c:1366 task_work_run+0x14e/0x250 kernel/task_work.c:239 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0xad8/0x2d70 kernel/exit.c:938 do_group_exit+0xd3/0x2a0 kernel/exit.c:1087 get_signal+0x2576/0x2610 kernel/signal.c:3017 arch_do_signal_or_restart+0x90/0x7e0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop kernel/entry/common.c:111 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x150/0x2a0 kernel/entry/common.c:218 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee3cb87a6a Code: Unable to access opcode bytes at 0x7fee3cb87a40. RSP: 002b:00007fffcccac688 EFLAGS: 00000202 ORIG_RAX: 0000000000000037 RAX: 0000000000000000 RBX: 00007fffcccac710 RCX: 00007fee3cb87a6a RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007fffcccac6ac R09: 00007fffcccacac7 R10: 00007fffcccac710 R11: 0000000000000202 R12: 00007fee3cd49500 R13: 00007fffcccac6ac R14: 0000000000000000 R15: 00007fee3cd4b000 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:proc_scheduler+0xc6/0x3c0 net/mptcp/ctrl.c:125 Code: 03 42 80 3c 38 00 0f 85 fe 02 00 00 4d 8b a4 24 08 09 00 00 48 b8 00 00 00 00 00 fc ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux daad878a509d69da1761106cb48c091dfe9d522d ~ c0e394fd6b887e84da17e38aaa6c1c104f9c86c2 -
Linux Linux 6.9 -

II. Public POCs for CVE-2025-21642

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III. Intelligence Information for CVE-2025-21642

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Patches & Fixes for CVE-2025-21642 (3)

Same Patch Batch · Linux · 2025-01-19 · 47 CVEs total

CVE-2024-57929 7.8 HIGH dm array: fix releasing a faulty array block twice in dm_array_cursor_end
CVE-2025-21631 7.8 HIGH block, bfq: fix waker_bfqq UAF after bfq_split_bfqq()
CVE-2025-21652 7.8 HIGH ipvlan: Fix use-after-free in ipvlan_get_iflink().
CVE-2024-57918 7.8 HIGH drm/amd/display: fix page fault due to max surface definition mismatch
CVE-2024-57926 7.8 HIGH drm/mediatek: Set private->all_drm_private[i]->drm to NULL if mtk_drm_bind returns err
CVE-2024-57921 7.8 HIGH drm/amdgpu: Add a lock when accessing the buddy trim function
CVE-2025-21646 7.5 HIGH afs: Fix the maximum cell name length
CVE-2025-21647 7.3 HIGH sched: sch_cake: add bounds checks to host bulk flow fairness counts
CVE-2025-21640 7.1 HIGH sctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy
CVE-2025-21638 7.1 HIGH sctp: sysctl: auth_enable: avoid using current->nsproxy
CVE-2025-21650 7.1 HIGH net: hns3: fixed hclge_fetch_pf_reg accesses bar space out of bounds issue
CVE-2025-21637 7.1 HIGH sctp: sysctl: udp_port: avoid using current->nsproxy
CVE-2024-57912 iio: pressure: zpa2326: fix information leak in triggered buffer
CVE-2024-57910 iio: light: vcnl4035: fix information leak in triggered buffer
CVE-2024-57925 ksmbd: fix a missing return value check bug
CVE-2024-57911 iio: dummy: iio_simply_dummy_buffer: fix information leak in triggered buffer
CVE-2024-57913 usb: gadget: f_fs: Remove WARN_ON in functionfs_bind
CVE-2024-57914 usb: typec: tcpci: fix NULL pointer issue on shared irq case
CVE-2024-57928 netfs: Fix enomem handling in buffered reads
CVE-2024-57927 nfs: Fix oops in nfs_netfs_init_request() when copying to cache

Showing top 20 of 47 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2025-21642

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