Linux Kernel up to 6.19.8 smb2_open use after free

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.1.166/6.6.129/6.12.77/6.18.18/6.19.8. This vulnerability affects the function smb2_open. This manipulation causes use after free. This vulnerability appears as CVE-2026-43378. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.1.166/6.6.129/6.12.77/6.18.18/6.19.8. Affected by this vulnerability is the function smb2_open. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: smb: server: fix use-after-free in smb2_open() The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is dereferenced after rcu_read_unlock(), creating a use-after-free window.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2026-43378 since 05/01/2026. The exploitation appears to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 325425 (Ubuntu 24.04 LTS : Linux kernel (NVIDIA) vulnerabilities (USN-8508-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.167, 6.6.130, 6.12.78, 6.18.19 or 6.19.9 eliminates this vulnerability. Applying the patch e1b21e6066615e7d3d3a7aa2677e415e563fd7cc/b720c84087cb547f23ce03eab93568c1769e4556/54b48ae83de8bb06e65079d96368efe359d4909c/8f5b1a7cb009a93c48e9e334a2f59a660f9afc07/190e5f808e8058640b408ccfed25440b441a718a/1e689a56173827669a35da7cb2a3c78ed5c53680 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 (325425) and CERT Bund (WID-SEC-2026-1454). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Red Hat OpenShift
  • Microsoft Azure Linux
  • Open Source Linux Kernel
  • Proxmox Virtual Environment

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔒

CNA Base Score: 9.8
CNA Vector (Linux): 🔒

CVSSv2info

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

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 325425
Nessus Name: Ubuntu 24.04 LTS : Linux kernel (NVIDIA) vulnerabilities (USN-8508-1)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.167/6.6.130/6.12.78/6.18.19/6.19.9
Patch: e1b21e6066615e7d3d3a7aa2677e415e563fd7cc/b720c84087cb547f23ce03eab93568c1769e4556/54b48ae83de8bb06e65079d96368efe359d4909c/8f5b1a7cb009a93c48e9e334a2f59a660f9afc07/190e5f808e8058640b408ccfed25440b441a718a/1e689a56173827669a35da7cb2a3c78ed5c53680

Timelineinfo

05/01/2026 CVE reserved
05/08/2026 +7 days Advisory disclosed
05/08/2026 +0 days VulDB entry created
07/27/2026 +80 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43378 (🔒)
GCVE (CVE): GCVE-0-2026-43378
GCVE (VulDB): GCVE-100-362233
CERT Bund: WID-SEC-2026-1454 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/08/2026 18:29
Updated: 07/27/2026 10:25
Changes: 05/08/2026 18:29 (58), 05/20/2026 06:17 (11), 05/21/2026 03:04 (11), 07/08/2026 13:17 (2), 07/27/2026 10:25 (9)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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