CVE-2025-39838 Details
Description
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
A NULL pointer dereference vulnerability has been identified in the Linux kernel's CIFS (Common Internet File System) implementation. This issue arises because a NULL pointer is passed to the function '__cifs_sfu_make_node' without proper validation. The unchecked NULL pointer is then passed to 'cifs_strndup_to_utf16', which forwards it to 'cifs_local_to_utf16_bytes'. Here, the NULL pointer is dereferenced, leading to a crash. The vulnerability affects several versions of the Linux kernel.
The vulnerability has been addressed by adding a NULL check for the 'src' parameter in the 'cifs_strndup_to_utf16' function. Users should apply the latest patches available in the Linux kernel stable tree to mitigate this issue.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
No SSVC data is available for this CVE.
References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://cert-portal.siemens.com/productcert/html/ssa-032379.html | siemens-SADP | |
| https://git.kernel.org/stable/c/1f797f062b5cf13a1c2bcc23285361baaa7c9260 | kernel.org | Patch |
| https://git.kernel.org/stable/c/3c26a8d30ed6b53a52a023ec537dc50a6d34a67a | kernel.org | Patch |
| https://git.kernel.org/stable/c/70bccd9855dae56942f2b18a08ba137bb54093a0 | kernel.org | Patch |
| https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html | CVE | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-476 | NULL Pointer Dereference | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| linux linux kernel | >= 6.12, < 6.12.46 >= 6.13, < 6.16.6 6.17 rc1 6.17 rc2 6.17 rc3 6.17 rc4 |
CPE
Remediation
| |
| debian debian linux | 11.0 |
CPE
Remediation
| |
Change History
7 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | siemens-SADP |
| Jun 17, 2026 | CVE Modified | kernel.org |
| May 12, 2026 | CVE Modified | siemens-SADP |
| Jan 23, 2026 | Initial Analysis | [email protected] |
| Jan 2, 2026 | CVE Modified | kernel.org |
| Nov 3, 2025 | CVE Modified | CVE |
| Sep 19, 2025 | New CVE Received | kernel.org |