Use-after-free in Linux kernel - CVE-2025-39951

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Main Vulnerability Database Vulnerabilities #VU116456

Use-after-free in Linux kernel - CVE-2025-39951

Published: October 4, 2025


Vulnerability identifier: #VU116456
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2025-39951
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the virtio_uml_probe() function in arch/um/drivers/virtio_uml.c. A local user can escalate privileges on the system.


Affected software

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

How to mitigate CVE-2025-39951

Install update from vendor's repository.

kernel - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
python3-perf-debuginfo - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
python3-perf - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
perf-debuginfo - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
perf - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools-devel - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools-debuginfo - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-tools - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-source - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-headers - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-devel - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-debugsource - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
kernel-debuginfo - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
bpftool-debuginfo - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
bpftool - addressed in versions 5.10.0-299.0.0.202, 6.6.0-138.0.0.119, 6.6.0-138.0.0.132
linux-aws-fips (Ubuntu package) - addressed in versions 5.15.0.170.97, 5.15.0-170.180+fips1, 5.15.0.1100.90, 5.15.0.1100.96, 5.15.0-1100.107+fips1, 5.15.0-1100.109+fips1, 6.8.0-106.106+fips1, 6.8.0-1050.53+fips1, 6.8.0-1052.55+fips1
linux (Ubuntu package) - addressed in versions 5.15.0.170.143, 5.15.0.170.159, 5.15.0-170.180, 5.15.0.170.180~20.04.1, 5.15.0-170.180~20.04.1, 5.15.0.170.180~20.04.3, 5.15.0-170.180~20.04.3, 5.15.0.1083.82, 5.15.0-1083.91, 5.15.0.1094.90, 5.15.0-1094.97, 5.15.0.1094.97~20.04.1, 5.15.0-1094.97~20.04.1, 5.15.0.1096.95, 5.15.0-1096.102, 5.15.0.1100.96, 5.15.0.1100.103, 5.15.0-1100.107, 5.15.0-1100.109, 6.8.0-106.106, 6.8.0-106.106.1, 6.8.0-106.106.1~22.04.1, 6.8.0-106.106~22.04.1, 6.8.0-1035.38, 6.8.0-1047.48, 6.8.0-1047.48~22.04.1, 6.8.0-1048.53, 6.8.0-1049.49, 6.8.0-1049.49~22.04.1, 6.8.0-1050.53, 6.8.0-1052.55, 6.8.0-1052.55~22.04.1
linux-nvidia-tegra-igx (Ubuntu package) - addressed in versions 5.15.0-1041.41+1, 5.15.0.1041.43
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0.1052.52, 5.15.0-1052.52, 5.15.0.1052.52~20.04.2, 5.15.0-1052.52~20.04.2
linux-intel-iotg-5.15 (Ubuntu package) - addressed in versions 5.15.0.1064.67, 5.15.0-1064.68, 5.15.0-1095.101~20.04.1, 5.15.0.1095.101~20.04.1
linux-gcp-5.15 (Ubuntu package) - addressed in versions 5.15.0.1092.88, 5.15.0-1092.97, 5.15.0.1097.93, 5.15.0-1097.103, 5.15.0-1097.103~20.04.1, 5.15.0.1097.103~20.04.1, 5.15.0-1100.109~20.04.1, 5.15.0.1100.109~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1092.94, 5.15.0.1092.96, 5.15.0.1099.103, 5.15.0-1099.108
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0.1095.95, 5.15.0-1095.96, 6.8.0-1049.52, 6.8.0-1049.52.1, 6.8.0-1049.52~22.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0.1095.95, 5.15.0-1095.101
linux-raspi (Ubuntu package) - addressed in versions 5.15.0.1097.95, 5.15.0-1097.100, 6.8.0-1050.54, 6.8.0-2040.41
linux-aws-5.15 (Ubuntu package) - addressed in versions 5.15.0.1100.107~20.04.1, 5.15.0-1100.107~20.04.2
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1109.94, 5.15.0-1109.118+fips1, 6.8.0-1052.58+fips1
linux-azure (Ubuntu package) - addressed in versions 5.15.0.1109.107, 5.15.0-1109.118, 6.8.0-1051.57
linux-azure-5.15 (Ubuntu package) - update to 5.15.0-1110.119~20.04.1
linux (Debian package) - update to 6.1.158-1
kernel-extra-modules - update to 6.6.0-138.0.0.132
linux-xilinx (Ubuntu package) - update to 6.8.0-1029.30
linux-aws-6.8 (Ubuntu package) - update to 6.8.0-1050.53~22.04.1
linux-azure-6.8 (Ubuntu package) - update to 6.8.0-1051.57~22.04.1
linux-realtime (Ubuntu package) - addressed in versions 6.8.1-1045.46, 6.8.1-1045.46~22.04.1

External References

Related Security Bulletins