Medium 5.5Published Sep 19, 2025

CVE-2025-39838cifs: prevent NULL pointer dereference in UTF16 conversion

Updated under an hour ago (Oct 27, 2026, 8:25 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: cifs: prevent NULL pointer dereference in UTF16 conversion There can be a NULL pointer dereference bug here. NULL is passed to __cifs_sfu_make_node without checks, which passes it unchecked to cifs_strndup_to_utf16, which in turn passes it to cifs_local_to_utf16_bytes where '*from' is dereferenced, causing a crash. This patch adds a check for NULL 'src' in cifs_strndup_to_utf16 and returns NULL early to prevent dereferencing NULL pointer. Found by Linux Verification Center (linuxtesting.org) with SVACE

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: May 12, 2026
First seen by InfoSec Signals: Oct 19, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	41d3f256c6a5e41eb32b87168399c0facd512dc0 builds before 1f797f062b5cf13a1c2bcc23285361baaa7c9260; 41d3f256c6a5e41eb32b87168399c0facd512dc0 builds before 3c26a8d30ed6b53a52a023ec537dc50a6d34a67a; from 41d3f256c6a5e41eb32b87168399c0facd512dc0 before 70bccd9855dae56942f2b18a08ba137bb54093a0	CNA record
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name)	before V5.0	CISA ADP
linux linux_kernel linux:linux_kernel	from 6.12 before 6.12.46; from 6.13 before 6.16.6; 6.17; 6.17; 6.17; 6.17	NVD
debian debian_linux debian:debian_linux	11.0	NVD

References

References

https://git.kernel.org/stable/c/1f797f062b5cf13a1c2bcc23285361baaa7c9260	patch
https://git.kernel.org/stable/c/3c26a8d30ed6b53a52a023ec537dc50a6d34a67a	patch
https://git.kernel.org/stable/c/70bccd9855dae56942f2b18a08ba137bb54093a0	patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	third-party-advisory
https://cert-portal.siemens.com/productcert/html/ssa-032379.html

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.