Linux Kernel up to 6.17-rc4 cifs __cifs_sfu_make_node null pointer dereference

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CTI Interest Score
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5.5$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.150/6.6.104/6.12.45/6.16.5/6.17-rc4. It has been classified as critical. This issue affects the function __cifs_sfu_make_node of the component cifs. The manipulation leads to null pointer dereference. This vulnerability is listed as CVE-2025-39838. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.1.150/6.6.104/6.12.45/6.16.5/6.17-rc4. It has been rated as critical. This issue affects the function __cifs_sfu_make_node of the component cifs. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. The summary by CVE is:

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

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2025-39838 since 04/16/2025. The exploitation is known to be easy. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 265467 (Linux Distros Unpatched Vulnerability : CVE-2025-39838), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.151, 6.6.105, 6.12.46, 6.16.6 or 6.17-rc5 eliminates this vulnerability. Applying the patch 65b98a7e65e7a8f3894d8760cd194eaf20504c99/1cfa5dd05847137f0fb3ce74ced80c0b4858d716/1f797f062b5cf13a1c2bcc23285361baaa7c9260/3c26a8d30ed6b53a52a023ec537dc50a6d34a67a/70bccd9855dae56942f2b18a08ba137bb54093a0 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (265467) and CERT Bund (WID-SEC-2025-2099). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • IBM QRadar SIEM
  • SUSE openSUSE
  • RESF Rocky Linux
  • Open Source Linux Kernel
  • Dell Secure Connect Gateway

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.5

VulDB Base Score: 5.7
VulDB Temp Score: 5.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 265467
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-39838

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.151/6.6.105/6.12.46/6.16.6/6.17-rc5
Patch: 65b98a7e65e7a8f3894d8760cd194eaf20504c99/1cfa5dd05847137f0fb3ce74ced80c0b4858d716/1f797f062b5cf13a1c2bcc23285361baaa7c9260/3c26a8d30ed6b53a52a023ec537dc50a6d34a67a/70bccd9855dae56942f2b18a08ba137bb54093a0

Timelineinfo

04/16/2025 CVE reserved
09/19/2025 +156 days Advisory disclosed
09/19/2025 +0 days VulDB entry created
01/23/2026 +126 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-39838 (🔒)
GCVE (CVE): GCVE-0-2025-39838
GCVE (VulDB): GCVE-100-325043
CERT Bund: WID-SEC-2025-2099 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 09/19/2025 18:13
Updated: 01/23/2026 04:34
Changes: 09/19/2025 18:13 (59), 09/23/2025 01:24 (2), 10/20/2025 19:02 (7), 11/03/2025 12:16 (1), 11/11/2025 22:33 (1), 11/29/2025 06:03 (1), 12/22/2025 10:25 (1), 01/23/2026 04:34 (10)
Complete: 🔍
Cache ID: 216::103

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