NULL pointer dereference in Linux

CVE-2025-39857

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.

EPSS: 0.001 (3.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-39857?
CVE-2025-39857 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2025-09-19.
How severe is CVE-2025-39857?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-39857 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.