Incorrect Calculation of Buffer Size in Linux kernel - CVE-2026-31478

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU127673

Incorrect Calculation of Buffer Size in Linux kernel - CVE-2026-31478

Published: April 24, 2026


Vulnerability identifier: #VU127673
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31478
CWE-ID: CWE-131
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper buffer size calculation in smb2_calc_max_out_buf_len() when handling SMB2 compound read responses. A remote user can send a specially crafted SMB request to cause a denial of service.


Affected software

Linux kernel
Debian Linux
Ubuntu
linux (Ubuntu package)
linux-kvm (Ubuntu package)
linux-gcp (Ubuntu package)
linux-aws (Ubuntu package)
linux-azure (Ubuntu package)
linux-raspi (Ubuntu package)
linux-oracle (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-gke (Ubuntu package)
linux-aws-5.15 (Ubuntu package)
linux-lowlatency-hwe-5.15 (Ubuntu package)
linux-hwe-5.15 (Ubuntu package)
linux-fips (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-tegra-igx (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure-fde-5.15 (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-gkeop (Ubuntu package)
linux-realtime (Ubuntu package)
linux-ibm (Ubuntu package)
linux-intel-iotg-5.15 (Ubuntu package)
linux-oracle-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-xilinx-zynqmp (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-hwe-6.17 (Ubuntu package)
linux-gcp-6.17 (Ubuntu package)
linux-oracle-6.17 (Ubuntu package)
linux-azure-6.17 (Ubuntu package)
linux-nvidia-6.17 (Ubuntu package)
linux-oem-6.17 (Ubuntu package)
linux-aws-6.17 (Ubuntu package)
linux-realtime-6.17 (Ubuntu package)
linux (Debian package)
linux-hwe-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-azure-fde-6.17 (Ubuntu package)

How to mitigate CVE-2026-31478

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 5.15.0-185.195, 6.8.0-134.134, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61~22.04.1, 6.8.0-1058.61+fips1, 6.8.0-1060.61, 6.8.0-1060.63~22.04.1, 6.8.0-1060.63+fips1, 6.8.0-1063.69, 6.8.0-1063.69+fips1, 6.8.1-1055.56~22.04.1, 6.8.1-1055.56, 6.17.0-40.40
linux-kvm (Ubuntu package) - update to 5.15.0-1103.108
linux-gcp (Ubuntu package) - addressed in versions 5.15.0-1111.121, 6.17.0-1020.22
linux-aws (Ubuntu package) - addressed in versions 5.15.0-1111.118, 6.17.0-1019.19
linux-azure (Ubuntu package) - addressed in versions 5.15.0-1116.125, 6.8.0-1063.71~22.04.1, 6.8.0-1063.71
linux-raspi (Ubuntu package) - addressed in versions 5.15.0-1105.108, 6.8.0-1060.64, 6.17.0-1021.21
linux-oracle (Ubuntu package) - addressed in versions 5.15.0-1108.114, 6.17.0-1018.18
linux-lowlatency (Ubuntu package) - update to 5.15.0-183.193
linux-gke (Ubuntu package) - update to 5.15.0-1107.113
linux-aws-5.15 (Ubuntu package) - update to 5.15.0-1111.118~20.04.1
linux-lowlatency-hwe-5.15 (Ubuntu package) - update to 5.15.0-183.193~20.04.1
linux-hwe-5.15 (Ubuntu package) - update to 5.15.0-185.195~20.04.1
linux-fips (Ubuntu package) - update to 5.15.0-185.195+fips1
linux-azure-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-nvidia (Ubuntu package) - update to 5.15.0-1106.107
linux-nvidia-tegra-igx (Ubuntu package) - update to 5.15.0-1052.52
linux-intel-iotg (Ubuntu package) - update to 5.15.0-1106.112
linux-azure-fde-5.15 (Ubuntu package) - update to 5.15.0-1116.125~20.04.1
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1105.109~20.04.1
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1063.63, 6.8.0-1029.30
linux-gkeop (Ubuntu package) - update to 5.15.0-1094.102
linux-realtime (Ubuntu package) - addressed in versions 5.15.0-1110.119, 6.17.0-1017.19
linux-ibm (Ubuntu package) - update to 5.15.0-1105.109
linux-intel-iotg-5.15 (Ubuntu package) - update to 5.15.0-1106.112~20.04.1
linux-oracle-5.15 (Ubuntu package) - update to 5.15.0-1108.114~20.04.1
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1111.121~20.04.1
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1063.63~20.04.1
linux-xilinx-zynqmp (Ubuntu package) - update to 5.15.0-1074.78
linux-intel-iot-realtime (Ubuntu package) - update to 5.15.0-1103.105
linux-gcp-fips (Ubuntu package) - update to 5.15.0-1111.121+fips1
linux-aws-fips (Ubuntu package) - update to 5.15.0-1111.118+fips1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0-1116.125+fips1, 6.8.0-134.134+fips1, 6.8.0-1062.69+fips1
linux-hwe-6.17 (Ubuntu package) - update to 6.17.0-40.40~24.04.1
linux-gcp-6.17 (Ubuntu package) - update to 6.17.0-1020.22~24.04.1
linux-oracle-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1
linux-azure-6.17 (Ubuntu package) - update to 6.17.0-1021.21~24.04.1
linux-nvidia-6.17 (Ubuntu package) - update to 6.17.0-1026.26
linux-oem-6.17 (Ubuntu package) - update to 6.17.0-1028.28
linux-aws-6.17 (Ubuntu package) - update to 6.17.0-1019.19~24.04.1
linux-realtime-6.17 (Ubuntu package) - update to 6.17.0-1017.19~24.04.1
linux (Debian package) - addressed in versions 6.1.170-1, 6.12.85-1
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1045.48, 6.8.0-1057.58~22.04.1, 6.8.0-1058.61.1, 6.8.0-1058.64, 6.8.0-1060.61~22.04.1, 6.8.0-1060.63~22.04.1, 6.8.0-1063.69~22.04.1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-azure-fde (Ubuntu package) - update to 6.8.0-1062.69
linux-raspi-realtime (Ubuntu package) - update to 6.8.0-2049.50
linux-azure-fde-6.17 (Ubuntu package) - update to 6.17.0-1018.18~24.04.1

External References

Related Security Bulletins