high 7.5

CVE-2025-39857 json

net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()

published 2025-09-19 13 mo ago modified 2026-10-19 20 d ago also EUVD-2025-30343

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits: 0; none known

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

BUG: kernel NULL pointer dereference, address: 00000000000002ec PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G OE 6.17.0-rc2+ #9 NONE Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 Workqueue: smc_hs_wq smc_listen_work [smc] RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc] ... Call Trace: <TASK> smcr_buf_map_link+0x211/0x2a0 [smc] __smc_buf_create+0x522/0x970 [smc] smc_buf_create+0x3a/0x110 [smc] smc_find_rdma_v2_device_serv+0x18f/0x240 [smc] ? smc_vlan_by_tcpsk+0x7e/0xe0 [smc] smc_listen_find_device+0x1dd/0x2b0 [smc] smc_listen_work+0x30f/0x580 [smc] process_one_work+0x18c/0x340 worker_thread+0x242/0x360 kthread+0xe7/0x220 ret_from_fork+0x13a/0x160 ret_from_fork_asm+0x1a/0x30 </TASK>

If the software RoCE device is used, ibdev->dma_device is a null pointer. As a result, the problem occurs. Null pointer detection is added to prevent problems.

Patch / fix

fixed in 2 distros 5 links 5

Linux Linux 6.1.151, 6.6.105, 6.12.46, 6.16.6, 6.17
Siemens SIMATIC CN 4100 V5.0

debian ubuntu suse opensuse azure linux

linux Debian 12 6.1.153-1
linux Debian 13 6.12.48-1
linux Debian 14 6.16.6-1

debian advisories DEBIAN-CVE-2025-39857

linux Ubuntu 24.04 LTS 6.8.0-106.106
linux-aws Ubuntu 24.04 LTS 6.8.0-1050.53
linux-gcp Ubuntu 24.04 LTS 6.8.0-1052.55
linux-gke Ubuntu 24.04 LTS 6.8.0-1048.53
linux-ibm Ubuntu 24.04 LTS 6.8.0-1049.49
linux-azure Ubuntu 24.04 LTS 6.8.0-1051.57
linux-gkeop Ubuntu 24.04 LTS 6.8.0-1035.38
linux-raspi Ubuntu 24.04 LTS 6.8.0-1050.54

ubuntu advisories UBUNTU-CVE-2025-39857

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 6.12.0-160000.6.1
kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
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 6.12.0-160000.6.1
kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1
kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2025:21074-1 SUSE-SU-2025:21139-1 SUSE-SU-2026:20560-1 SUSE-SU-2025:21179-1 SUSE-SU-2025:20870-1 SUSE-SU-2025:20898-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

kernel Azure Linux 3.0 6.6.112.1-1

azure linux advisories AZL-67532

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2025-39857 updated 2026-11-05 cvss 5.5

kernel: net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()

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
affected: no fix available “Fix deferred”
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
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

cisa ICSA-26-134-10 updated 2026-05-14 cvss 7.0

Siemens SIMATIC

Siemens SIMATIC CN 4100 < 5.0
affected: fixed in V5.0 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 24 d ago (2026-10-15)

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Linux Linux
Siemens SIMATIC CN 4100

Classification

Weakness

CWE-476 NULL Pointer Dereference

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2025-39857
NVD CVE-2025-39857

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.

Summary