Linux Kernel up to 7.0-rc3 USB check_command_size_in_blocks integer overflow

CVSS Meta Temp Score
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CTI Interest Score
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6.6$0-$5k0.00

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.0-rc3 and classified as critical. Affected by this issue is the function check_command_size_in_blocks of the component USB Handler. The manipulation results in integer overflow. This vulnerability was named CVE-2026-31412. There is no available exploit. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 7.0-rc3. Affected is the function check_command_size_in_blocks of the component USB Handler. The manipulation with an unknown input leads to a integer overflow vulnerability. CWE is classifying the issue as CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_mass_storage: Fix potential integer overflow in check_command_size_in_blocks() The `check_command_size_in_blocks()` function calculates the data size in bytes by left shifting `common->data_size_from_cmnd` by the block size (`common->curlun->blkbits`). However, it does not validate whether this shift operation will cause an integer overflow. Initially, the block size is set up in `fsg_lun_open()` , and the `common->data_size_from_cmnd` is set up in `do_scsi_command()`. During initialization, there is no integer overflow check for the interaction between two variables. So if a malicious USB host sends a SCSI READ or WRITE command requesting a large amount of data (`common->data_size_from_cmnd`), the left shift operation can wrap around. This results in a truncated data size, which can bypass boundary checks and potentially lead to memory corruption or out-of-bounds accesses. Fix this by using the check_shl_overflow() macro to safely perform the shift and catch any overflows.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-31412 since 03/09/2026. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/20/2026).

The vulnerability scanner Nessus provides a plugin with the ID 305977 (Linux Distros Unpatched Vulnerability : CVE-2026-31412), 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, 6.19.9 or 7.0-rc4 eliminates this vulnerability. Applying the patch 91817ad5452defe69bc7bc0e355f0ed5d01125cc/ce0caaed5940162780c5c223b8ae54968a5f059b/228b37936376143f4b60cc6828663f6eaceb81b5/3428dc5520c811e66622b2f5fa43341bf9a1f8b3/387ebb0453b99d71491419a5dc4ab4bee0cacbac/8479891d1f04a8ce55366fe4ca361ccdb96f02e1 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 (305977) and CERT Bund (WID-SEC-2026-1049). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Open Source Linux Kernel

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.6

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

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Integer overflow
CWE: CWE-190 / CWE-189
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: 305977
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-31412

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.167/6.6.130/6.12.78/6.18.19/6.19.9/7.0-rc4
Patch: 91817ad5452defe69bc7bc0e355f0ed5d01125cc/ce0caaed5940162780c5c223b8ae54968a5f059b/228b37936376143f4b60cc6828663f6eaceb81b5/3428dc5520c811e66622b2f5fa43341bf9a1f8b3/387ebb0453b99d71491419a5dc4ab4bee0cacbac/8479891d1f04a8ce55366fe4ca361ccdb96f02e1

Timelineinfo

03/09/2026 CVE reserved
04/10/2026 +31 days Advisory disclosed
04/10/2026 +0 days VulDB entry created
05/20/2026 +40 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-31412 (🔒)
GCVE (CVE): GCVE-0-2026-31412
GCVE (VulDB): GCVE-100-356808
CERT Bund: WID-SEC-2026-1049 - Linux Kernel: Schwachstelle ermöglicht Denial of Service oder Codeausführung

Entryinfo

Created: 04/10/2026 15:48
Updated: 05/20/2026 22:32
Changes: 04/10/2026 15:48 (59), 04/11/2026 03:27 (7), 04/12/2026 01:24 (2), 05/20/2026 22:32 (11)
Complete: 🔍
Cache ID: 216::103

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