NULL pointer dereference in Linux kernel - CVE-2026-31577

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Main Vulnerability Database Vulnerabilities #VU127818

NULL pointer dereference in Linux kernel - CVE-2026-31577

Published: April 25, 2026


Vulnerability identifier: #VU127818
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-31577
CWE-ID: CWE-476
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

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

The vulnerability exists due to a NULL pointer dereference in nilfs_mdt_save_to_shadow_map() when handling NILFS_IOCTL_CLEAN_SEGMENTS immediately after mount before any btree operation has occurred on the DAT inode. A local user can invoke the ioctl in that state to cause a denial of service.

The issue occurs because the DAT inode's i_assoc_inode may remain uninitialized until a btree operation is performed.


Affected software

Linux kernel
Debian Linux
Ubuntu
openEuler
linux (Ubuntu package)
linux-realtime (Ubuntu package)
linux-oracle (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-azure (Ubuntu package)
linux-raspi (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-ibm (Ubuntu package)
linux-azure-fde (Ubuntu package)
perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
python3-perf
kernel-tools-debuginfo
perf
kernel-tools-devel
kernel-source
python3-perf-debuginfo
kernel-tools
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-ibm-5.15 (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-gcp-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-fips (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux (Debian package)

How to mitigate CVE-2026-31577

Install security update from vendor's repository.

linux (Ubuntu package) - addressed in versions 5.15.0-184.194~20.04.1, 5.15.0-184.194, 5.15.0-186.196~20.04.1, 5.15.0-186.196, 5.15.0-1075.79, 5.15.0-1095.103, 5.15.0-1104.109, 5.15.0-1108.114, 5.15.0-1111.120+fips1, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 5.15.0.184.155, 5.15.0.186.166, 5.15.0.1075.78, 5.15.0.1095.94, 5.15.0.1104.100, 5.15.0.1108.107, 5.15.0.1111.115, 5.15.0.1112.102, 5.15.0.1112.109, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72~22.04.1, 6.8.0-1064.72, 6.8.1-1056.57~22.04.2, 6.8.1-1056.57, 7.0.0-27.27
linux-realtime (Ubuntu package) - update to 7.0.0-27.27.1
linux-oracle (Ubuntu package) - update to 7.0.0-1007.7
linux-aws (Ubuntu package) - addressed in versions 5.15.0-186.196+fips1, 5.15.0-1106.110, 5.15.0-1107.108, 5.15.0-1112.119~20.04.1, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0.186.109, 5.15.0.1106.103, 5.15.0.1107.107, 5.15.0.1112.108, 5.15.0.1112.115, 6.8.0-1061.64+1, 7.0.0-1008.8
linux-gcp (Ubuntu package) - update to 7.0.0-1007.7
linux-azure (Ubuntu package) - addressed in versions 5.15.0-1109.115, 5.15.0-1117.126, 5.15.0.1109.105, 5.15.0.1117.115, 6.8.0-1063.71~22.04.1, 6.8.0-1063.71, 7.0.0-1010.10
linux-raspi (Ubuntu package) - addressed in versions 5.15.0-1106.109, 5.15.0.1106.104, 6.8.0-1061.65, 6.8.0-2050.52, 7.0.0-1014.14
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62~22.04.1, 6.8.0-1059.62, 6.8.0-1059.62.1, 7.0.0-1013.13
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62~22.04.1, 6.8.0-1061.62, 7.0.0-1009.9
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69, 7.0.0-1009.9
perf-debuginfo - update to 5.10.0-328.0.0.229
kernel - update to 5.10.0-328.0.0.229
bpftool - update to 5.10.0-328.0.0.229
bpftool-debuginfo - update to 5.10.0-328.0.0.229
kernel-debuginfo - update to 5.10.0-328.0.0.229
kernel-debugsource - update to 5.10.0-328.0.0.229
kernel-devel - update to 5.10.0-328.0.0.229
kernel-headers - update to 5.10.0-328.0.0.229
python3-perf - update to 5.10.0-328.0.0.229
kernel-tools-debuginfo - update to 5.10.0-328.0.0.229
perf - update to 5.10.0-328.0.0.229
kernel-tools-devel - update to 5.10.0-328.0.0.229
kernel-source - update to 5.10.0-328.0.0.229
python3-perf-debuginfo - update to 5.10.0-328.0.0.229
kernel-tools - update to 5.10.0-328.0.0.229
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0-1064.66, 5.15.0.1053.55, 5.15.0.1064.64
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0-1107.113~20.04.1, 5.15.0.1104.108
linux-ibm-5.15 (Ubuntu package) - update to 5.15.0-1106.110~20.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0-1107.113, 5.15.0.1107.106
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-gcp-5.15 (Ubuntu package) - update to 5.15.0-1112.122~20.04.1
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0-1117.126+fips1, 5.15.0.1117.102, 6.8.0-1063.71+fips2
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2~22.04.1, 6.8.0-136.136.2, 6.8.0-1058.61
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64~22.04.1, 6.8.0-1061.64+fips1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1
linux (Debian package) - update to 6.12.85-1

External References

Related Security Bulletins