CVE-2025-39828

Published Sep 16, 2025

Last updated 3 months ago

CVSS high 7.8

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: atm: atmtcp: Prevent arbitrary write in atmtcp_recv_control(). syzbot reported the splat below. [0] When atmtcp_v_open() or atmtcp_v_close() is called via connect() or close(), atmtcp_send_control() is called to send an in-kernel special message. The message has ATMTCP_HDR_MAGIC in atmtcp_control.hdr.length. Also, a pointer of struct atm_vcc is set to atmtcp_control.vcc. The notable thing is struct atmtcp_control is uAPI but has a space for an in-kernel pointer. struct atmtcp_control { struct atmtcp_hdr hdr; /* must be first */ ... atm_kptr_t vcc; /* both directions */ ... } __ATM_API_ALIGN; typedef struct { unsigned char _[8]; } __ATM_API_ALIGN atm_kptr_t; The special message is processed in atmtcp_recv_control() called from atmtcp_c_send(). atmtcp_c_send() is vcc->dev->ops->send() and called from 2 paths: 1. .ndo_start_xmit() (vcc->send() == atm_send_aal0()) 2. vcc_sendmsg() The problem is sendmsg() does not validate the message length and userspace can abuse atmtcp_recv_control() to overwrite any kptr by atmtcp_control. Let's add a new ->pre_send() hook to validate messages from sendmsg(). [0]: Oops: general protection fault, probably for non-canonical address 0xdffffc00200000ab: 0000 [#1] SMP KASAN PTI KASAN: probably user-memory-access in range [0x0000000100000558-0x000000010000055f] CPU: 0 UID: 0 PID: 5865 Comm: syz-executor331 Not tainted 6.17.0-rc1-syzkaller-00215-gbab3ce404553 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:atmtcp_recv_control drivers/atm/atmtcp.c:93 [inline] RIP: 0010:atmtcp_c_send+0x1da/0x950 drivers/atm/atmtcp.c:297 Code: 4d 8d 75 1a 4c 89 f0 48 c1 e8 03 42 0f b6 04 20 84 c0 0f 85 15 06 00 00 41 0f b7 1e 4d 8d b7 60 05 00 00 4c 89 f0 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 13 06 00 00 66 41 89 1e 4d 8d 75 1c 4c RSP: 0018:ffffc90003f5f810 EFLAGS: 00010203 RAX: 00000000200000ab RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff88802a510000 RSI: 00000000ffffffff RDI: ffff888030a6068c RBP: ffff88802699fb40 R08: ffff888030a606eb R09: 1ffff1100614c0dd R10: dffffc0000000000 R11: ffffffff8718fc40 R12: dffffc0000000000 R13: ffff888030a60680 R14: 000000010000055f R15: 00000000ffffffff FS: 00007f8d7e9236c0(0000) GS:ffff888125c1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000000045ad50 CR3: 0000000075bde000 CR4: 00000000003526f0 Call Trace: <TASK> vcc_sendmsg+0xa10/0xc60 net/atm/common.c:645 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x219/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2614 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668 __sys_sendmsg net/socket.c:2700 [inline] __do_sys_sendmsg net/socket.c:2705 [inline] __se_sys_sendmsg net/socket.c:2703 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703 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: 0033:0x7f8d7e96a4a9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8d7e923198 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f8d7e9f4308 RCX: 00007f8d7e96a4a9 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000005 RBP: 00007f8d7e9f4300 R08: 65732f636f72702f R09: 65732f636f72702f R10: 65732f636f72702f R11: 0000000000000246 R12: 00007f8d7e9c10ac R13: 00007f8d7e9231a0 R14: 0000200000000200 R15: 0000200000000250 </TASK> Modules linked in:
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
linux_kernel, debian_linux

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
NVD-CWE-noinfo

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. In the Linux kernel, the following vulnerability has been resolved: net: usb: cdc_ncm: add ndpoffset to NDP32 nframes bounds check The same bounds-check bug fixed for NDP16 in the previous patch also exists in cdc_ncm_rx_verify_ndp32(). The DPE array size is validated against the total skb length without accounting for ndpoffset, allowing out-of-bounds reads when the NDP32 is placed near the end of the NTB. Add ndpoffset to the nframes bounds check and use struct_size_t() to express the NDP-plus-DPE-array size more clearly. Compile-tested only.•CVE-2026-23447
  2. In the Linux kernel, the following vulnerability has been resolved: net: usb: aqc111: Do not perform PM inside suspend callback syzbot reports "task hung in rpm_resume" This is caused by aqc111_suspend calling the PM variant of its write_cmd routine. The simplified call trace looks like this: rpm_suspend() usb_suspend_both() - here udev->dev.power.runtime_status == RPM_SUSPENDING aqc111_suspend() - called for the usb device interface aqc111_write32_cmd() usb_autopm_get_interface() pm_runtime_resume_and_get() rpm_resume() - here we call rpm_resume() on our parent rpm_resume() - Here we wait for a status change that will never happen. At this point we block another task which holds rtnl_lock and locks up the whole networking stack. Fix this by replacing the write_cmd calls with their _nopm variants•CVE-2026-23446
  3. In the Linux kernel, the following vulnerability has been resolved: igc: fix page fault in XDP TX timestamps handling If an XDP application that requested TX timestamping is shutting down while the link of the interface in use is still up the following kernel splat is reported: [ 883.803618] [ T1554] BUG: unable to handle page fault for address: ffffcfb6200fd008 ... [ 883.803650] [ T1554] Call Trace: [ 883.803652] [ T1554] <TASK> [ 883.803654] [ T1554] igc_ptp_tx_tstamp_event+0xdf/0x160 [igc] [ 883.803660] [ T1554] igc_tsync_interrupt+0x2d5/0x300 [igc] ... During shutdown of the TX ring the xsk_meta pointers are left behind, so that the IRQ handler is trying to touch them. This issue is now being fixed by cleaning up the stale xsk meta data on TX shutdown. TX timestamps on other queues remain unaffected.•CVE-2026-23445
  4. In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure ieee80211_tx_prepare_skb() has three error paths, but only two of them free the skb. The first error path (ieee80211_tx_prepare() returning TX_DROP) does not free it, while invoke_tx_handlers() failure and the fragmentation check both do. Add kfree_skb() to the first error path so all three are consistent, and remove the now-redundant frees in callers (ath9k, mt76, mac80211_hwsim) to avoid double-free. Document the skb ownership guarantee in the function's kdoc.•CVE-2026-23444
  5. In the Linux kernel, the following vulnerability has been resolved: ACPI: processor: Fix previous acpi_processor_errata_piix4() fix After commi f132e089fe89 ("ACPI: processor: Fix NULL-pointer dereference in acpi_processor_errata_piix4()"), device pointers may be dereferenced after dropping references to the device objects pointed to by them, which may cause a use-after-free to occur. Moreover, debug messages about enabling the errata may be printed if the errata flags corresponding to them are unset. Address all of these issues by moving message printing to the points in the code where the errata flags are set.•CVE-2026-23443

References

Sources include official advisories and independent security research.