CVE-2025-39857

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

MEDIUM
5.5
CVSS Score
Published: September 19, 2025 at 03:26 PM UTC
Updated: October 19, 2026 at 09:10 PM UTC
3 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC CN 4100

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync() 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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.0 ≤ v < 6.1.1516.13 ≤ v < 6.16.66.2 ≤ v < 6.6.1056.7 ≤ v < 6.12.460ef69e788411cba2af017db731a9fc62d255e9ac6.176.17 rc16.17 rc26.17 rc36.17 rc4
Vendor states this is fixed in 0cdf1fd8fc59d44a48c694324611136910301ef9 (fixed)
Vendor states this is fixed in 34f17cbe027050b8d5316ea1b6f9bd7c378e92de (fixed)
Vendor states this is fixed in ba1e9421cf1a8369d25c3832439702a015d6b5f9 (fixed)
Vendor states this is fixed in eb929910bd4b4165920fa06a87b22cc6cae92e0e (fixed)
Vendor states this is fixed in f18d9b3abf9c6587372cc702f963a7592277ed56 (fixed)
Vendor states this is fixed in 6.0 (unaffected)
Vendor states this is fixed in 6.1.151 (unaffected)
Vendor states this is fixed in 6.12.46 (unaffected)
Vendor states this is fixed in 6.16.6 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.6.105 (unaffected)
v < V5.0
Affected range stops below V5.0, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-476

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