Linux Kernel up to 6.19.10 ksmbd offsetof buffer overflow

CVSS Meta Temp Score
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CTI Interest Score
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7.6$5k-$25k0.00

Summaryinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.19.10. This vulnerability affects the function offsetof of the component ksmbd. The manipulation leads to buffer overflow. This vulnerability is traded as CVE-2026-31478. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.19.10 and classified as critical. This issue affects the function offsetof of the component ksmbd. The manipulation with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"), response buffer management was changed to use dynamic iov array. In the new design, smb2_calc_max_out_buf_len() expects the second argument (hdr2_len) to be the offset of ->Buffer field in the response structure, not a hardcoded magic number. Fix the remaining call sites to use the correct offsetof() value.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-31478 since 03/09/2026. The exploitation is known to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/25/2026).

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 5.15.203, 6.1.168, 6.6.131, 6.12.80, 6.18.21 or 6.19.11 eliminates this vulnerability. Applying the patch 70b4c414889492c522b6e4331562360f49be2361/9a7166f0ef8cbb7bb48dd05e2471d995566003f5/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683/6aef1765d6807e0f027cd87f6ac973eb0879a46d/80824c7e527b70cf9039534e60aff592e8f209d1/4cb537ae4f37d7d0f617815ed4bed7173fb50861/0e55f63dd08f09651d39e1b709a91705a8a0ddcb 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-2026-1252). 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
  • Open Source Linux Kernel
  • Siemens SIMATIC S7
  • 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: 8.0
VulDB Meta Temp Score: 7.6

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

CVSSv2info

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

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

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 5.15.203/6.1.168/6.6.131/6.12.80/6.18.21/6.19.11
Patch: 70b4c414889492c522b6e4331562360f49be2361/9a7166f0ef8cbb7bb48dd05e2471d995566003f5/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683/6aef1765d6807e0f027cd87f6ac973eb0879a46d/80824c7e527b70cf9039534e60aff592e8f209d1/4cb537ae4f37d7d0f617815ed4bed7173fb50861/0e55f63dd08f09651d39e1b709a91705a8a0ddcb

Timelineinfo

03/09/2026 CVE reserved
04/22/2026 +43 days Advisory disclosed
04/22/2026 +0 days VulDB entry created
07/25/2026 +94 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31478 (🔒)
GCVE (CVE): GCVE-0-2026-31478
GCVE (VulDB): GCVE-100-358889
CERT Bund: WID-SEC-2026-1252 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/22/2026 17:10
Updated: 07/25/2026 13:57
Changes: 04/22/2026 17:10 (59), 06/17/2026 23:37 (7), 07/08/2026 03:31 (2), 07/25/2026 13:57 (3)
Complete: 🔍
Cache ID: 216::103

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

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