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Fencer Vulns
high 7.8

CVE-2025-40012 json

net/smc: fix warning in smc_rx_splice() when calling get_page()

published 2025-10-20 12 mo ago modified 2026-10-19 20 d ago also EUVD-2025-35068

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix warning in smc_rx_splice() when calling get_page()

smc_lo_register_dmb() allocates DMB buffers with kzalloc(), which are later passed to get_page() in smc_rx_splice(). Since kmalloc memory is not page-backed, this triggers WARN_ON_ONCE() in get_page() and prevents holding a refcount on the buffer. This can lead to use-after-free if the memory is released before splice_to_pipe() completes.

Use folio_alloc() instead, ensuring DMBs are page-backed and safe for get_page().

WARNING: CPU: 18 PID: 12152 at ./include/linux/mm.h:1330 smc_rx_splice+0xaf8/0xe20 [smc] CPU: 18 UID: 0 PID: 12152 Comm: smcapp Kdump: loaded Not tainted 6.17.0-rc3-11705-g9cf4672ecfee #10 NONE Hardware name: IBM 3931 A01 704 (z/VM 7.4.0) Krnl PSW : 0704e00180000000 000793161032696c (smc_rx_splice+0xafc/0xe20 [smc]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 001cee80007d3001 00077400000000f8 0000000000000005 0000000000000001 001cee80007d3006 0007740000001000 001c000000000000 000000009b0c99e0 0000000000001000 001c0000000000f8 001c000000000000 000003ffcc6f7c88 0007740003e98000 0007931600000005 000792969b2ff7b8 Krnl Code: 0007931610326960: af000000 mc 0,0 0007931610326964: a7f4ff43 brc 15,00079316103267ea #0007931610326968: af000000 mc 0,0 >000793161032696c: a7f4ff3f brc 15,00079316103267ea 0007931610326970: e320f1000004 lg %r2,256(%r15) 0007931610326976: c0e53fd1b5f5 brasl %r14,000793168fd5d560 000793161032697c: a7f4fbb5 brc 15,00079316103260e6 0007931610326980: b904002b lgr %r2,%r11 Call Trace: smc_rx_splice+0xafc/0xe20 [smc] smc_rx_splice+0x756/0xe20 [smc]) smc_rx_recvmsg+0xa74/0xe00 [smc] smc_splice_read+0x1ce/0x3b0 [smc] sock_splice_read+0xa2/0xf0 do_splice_read+0x198/0x240 splice_file_to_pipe+0x7e/0x110 do_splice+0x59e/0xde0 __do_splice+0x11a/0x2d0 __s390x_sys_splice+0x140/0x1f0 __do_syscall+0x122/0x280 system_call+0x6e/0x90 Last Breaking-Event-Address: smc_rx_splice+0x960/0xe20 [smc] ---[ end trace 0000000000000000 ]---

Patch / fix

  • Linux Linux 6.12.50, 6.16.10, 6.17
  • linux Debian 13 6.12.57-1
  • linux Debian 14 6.16.10-1

debian advisories DEBIAN-CVE-2025-40012

  • linux Ubuntu 25.10 6.17.0-6.6
  • linux-aws Ubuntu 25.10 6.17.0-1003.3
  • linux-gcp Ubuntu 25.10 6.17.0-1003.3
  • linux-azure Ubuntu 25.10 6.17.0-1006.6
  • linux-raspi Ubuntu 25.10 6.17.0-1004.4
  • linux-riscv Ubuntu 25.10 6.17.0-6.6.1
  • linux-oracle Ubuntu 25.10 6.17.0-1003.3
  • linux-realtime Ubuntu 25.10 6.17.0-1002.3

ubuntu advisories UBUNTU-CVE-2025-40012

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-rt Linux Micro 6.2 6.12.0-160000.7.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.7.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.7.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.7.1

suse advisories SUSE-SU-2025:21080-1SUSE-SU-2025:21147-1SUSE-SU-2025:21180-1SUSE-SU-2026:20561-1SUSE-SU-2025:4141-1SUSE-SU-2025:4132-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.7.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.7.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.7.1

opensuse advisories openSUSE-SU-2025:20091-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-40012 updated

kernel: net/smc: fix warning in smc_rx_splice() when calling get_page()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.