Memory leak in Linux kernel - CVE-2025-39720

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Main Vulnerability Database Vulnerabilities #VU114901

Memory leak in Linux kernel - CVE-2025-39720

Published: September 8, 2025


Vulnerability identifier: #VU114901
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-2025-39720
CWE-ID: CWE-401
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to memory leak within the smb_send_parent_lease_break_noti(), smb_lazy_parent_lease_break_close() and smb_break_all_levII_oplock() functions in fs/smb/server/oplock.c. A local user can perform a denial of service (DoS) attack.


Affected software

Linux kernel
Debian Linux
Ubuntu
openEuler
python3-perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
kernel-source
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf
kernel-extra-modules
linux (Ubuntu package)
linux-aws-fips (Ubuntu package)
linux-lowlatency (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-xilinx (Ubuntu package)
linux-aws (Ubuntu package)
linux-gcp (Ubuntu package)
linux-ibm (Ubuntu package)
linux-nvidia-lowlatency (Ubuntu package)
linux-azure (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-gcp-6.8 (Ubuntu package)
linux-azure-6.8 (Ubuntu package)
linux-raspi-realtime (Ubuntu package)
linux-realtime-6.8 (Ubuntu package)
linux (Debian package)

How to mitigate CVE-2025-39720

Install update from vendor's repository.

python3-perf-debuginfo - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
bpftool - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
bpftool-debuginfo - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-debuginfo - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-debugsource - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-devel - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-headers - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-source - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools-debuginfo - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools-devel - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
perf - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
perf-debuginfo - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
python3-perf - addressed in versions 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-extra-modules - update to 6.6.0-138.0.0.132
linux (Ubuntu package) - addressed in versions 6.8.0-100.100, 6.8.0-1047.51
linux-aws-fips (Ubuntu package) - addressed in versions 6.8.0-100.100+fips1, 6.8.0-1046.49+fips1
linux-lowlatency (Ubuntu package) - update to 6.8.0-100.100.1
linux-hwe-6.8 (Ubuntu package) - addressed in versions 6.8.0-100.100.1~22.04.1, 6.8.0-100.100~22.04.1
linux-xilinx (Ubuntu package) - addressed in versions 6.8.0-1023.24, 6.8.0.1023.24
linux-aws (Ubuntu package) - addressed in versions 6.8.0-1030.33, 6.8.0-1043.44, 6.8.0-1043.44~22.04.1, 6.8.0-1046.49~22.04.1
linux-gcp (Ubuntu package) - addressed in versions 6.8.0-1043.48, 6.8.0-1047.50~22.04.2
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1044.44, 6.8.0-1044.44~22.04.1
linux-nvidia-lowlatency (Ubuntu package) - update to 6.8.0-1046.49.1
linux-azure (Ubuntu package) - update to 6.8.0-1046.52
linux-azure-fips (Ubuntu package) - update to 6.8.0-1046.52+fips1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1047.50+fips1
linux-gcp-6.8 (Ubuntu package) - update to 6.8.0-1047.50~22.04.2
linux-azure-6.8 (Ubuntu package) - update to 6.8.0-1051.57~22.04.1
linux-raspi-realtime (Ubuntu package) - addressed in versions 6.8.0-2037.38, 6.8.1-1041.42
linux-realtime-6.8 (Ubuntu package) - update to 6.8.1-1041.42~22.04.1
linux (Debian package) - update to 6.12.48-1

External References

Related Security Bulletins