Use of uninitialized resource in Linux kernel - CVE-2025-21813

Vulnerability identifier: #VU105154

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-2025-21813

CWE-ID: CWE-908

Exploitation vector: Local access

Exploit availability: No public exploit available

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

The vulnerability exists due to use of uninitialized resource within the tmigr_setup_groups() function in kernel/time/timer_migration.c. A local user can perform a denial of service (DoS) attack.

Linux kernel
Ubuntu
linux-image-realtime (Ubuntu package)
linux-image-6.11.0-1009-realtime (Ubuntu package)
linux-image-generic (Ubuntu package)
linux-image-virtual (Ubuntu package)
linux-image-generic-64k (Ubuntu package)
linux-image-6.11.0-25-generic-64k (Ubuntu package)
linux-image-6.11.0-25-generic (Ubuntu package)
linux-image-generic-64k-hwe-24.04 (Ubuntu package)
linux-image-generic-hwe-24.04 (Ubuntu package)
linux-image-virtual-hwe-24.04 (Ubuntu package)
linux-image-raspi (Ubuntu package)
linux-image-6.11.0-1012-raspi (Ubuntu package)
linux-image-aws (Ubuntu package)
linux-image-6.11.0-1013-aws (Ubuntu package)
linux-image-lowlatency-64k (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-6.11.0-1013-lowlatency (Ubuntu package)
linux-image-6.11.0-1013-lowlatency-64k (Ubuntu package)
linux-image-lowlatency-hwe-24.04 (Ubuntu package)
linux-image-lowlatency-64k-hwe-24.04 (Ubuntu package)
linux-image-6.11.0-1014-gcp (Ubuntu package)
linux-image-6.11.0-1014-azure (Ubuntu package)
linux-image-6.11.0-1014-azure-fde (Ubuntu package)
linux-image-azure (Ubuntu package)
linux-image-azure-fde (Ubuntu package)
linux-image-gcp-64k (Ubuntu package)
linux-image-gcp (Ubuntu package)
linux-image-6.11.0-1014-gcp-64k (Ubuntu package)
linux-image-oracle (Ubuntu package)
linux-image-6.11.0-1015-oracle (Ubuntu package)
linux-image-6.11.0-1015-oracle-64k (Ubuntu package)
linux-image-oracle-64k (Ubuntu package)
linux-image-6.11.0-1021-oem (Ubuntu package)
linux-image-oem-24.04b (Ubuntu package)

Install update from vendor's website.

Linux kernel - update to 6.12.14
linux-image-realtime (Ubuntu package) - update to Ubuntu Pro
linux-image-6.11.0-1009-realtime (Ubuntu package) - update to Ubuntu Pro
linux-image-generic (Ubuntu package) - update to 6.11.0-25.25
linux-image-virtual (Ubuntu package) - update to 6.11.0-25.25
linux-image-generic-64k (Ubuntu package) - update to 6.11.0-25.25
linux-image-6.11.0-25-generic-64k (Ubuntu package) - addressed in versions 6.11.0-25.25, 6.11.0-25.25~24.04.1
linux-image-6.11.0-25-generic (Ubuntu package) - addressed in versions 6.11.0-25.25, 6.11.0-25.25~24.04.1
linux-image-generic-64k-hwe-24.04 (Ubuntu package) - update to 6.11.0-25.25~24.04.1
linux-image-generic-hwe-24.04 (Ubuntu package) - update to 6.11.0-25.25~24.04.1
linux-image-virtual-hwe-24.04 (Ubuntu package) - update to 6.11.0-25.25~24.04.1
linux-image-raspi (Ubuntu package) - update to 6.11.0-1012.12
linux-image-6.11.0-1012-raspi (Ubuntu package) - update to 6.11.0-1012.12
linux-image-aws (Ubuntu package) - update to 6.11.0-1013.14
linux-image-6.11.0-1013-aws (Ubuntu package) - update to 6.11.0-1013.14
linux-image-lowlatency-64k (Ubuntu package) - update to 6.11.0-1013.14
linux-image-lowlatency (Ubuntu package) - update to 6.11.0-1013.14
linux-image-6.11.0-1013-lowlatency (Ubuntu package) - addressed in versions 6.11.0-1013.14, 6.11.0-1013.14~24.04.1
linux-image-6.11.0-1013-lowlatency-64k (Ubuntu package) - addressed in versions 6.11.0-1013.14, 6.11.0-1013.14~24.04.1
linux-image-lowlatency-hwe-24.04 (Ubuntu package) - update to 6.11.0-1013.14~24.04.1
linux-image-lowlatency-64k-hwe-24.04 (Ubuntu package) - update to 6.11.0-1013.14~24.04.1
linux-image-6.11.0-1014-gcp (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-6.11.0-1014-azure (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-6.11.0-1014-azure-fde (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-azure (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-azure-fde (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-gcp-64k (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-gcp (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-6.11.0-1014-gcp-64k (Ubuntu package) - addressed in versions 6.11.0-1014.14, 6.11.0-1014.14~24.04.1
linux-image-oracle (Ubuntu package) - update to 6.11.0-1015.16
linux-image-6.11.0-1015-oracle (Ubuntu package) - update to 6.11.0-1015.16
linux-image-6.11.0-1015-oracle-64k (Ubuntu package) - update to 6.11.0-1015.16
linux-image-oracle-64k (Ubuntu package) - update to 6.11.0-1015.16
linux-image-6.11.0-1021-oem (Ubuntu package) - update to 6.11.0-1021.21
linux-image-oem-24.04b (Ubuntu package) - update to 6.11.0-1021.21

• https://git.kernel.org/stable/c/6f449d8fa1808a7f9ee644866bbc079285dbefdd
• https://git.kernel.org/stable/c/868c9037df626b3c245ee26a290a03ae1f9f58d3
• https://git.kernel.org/stable/c/c6dd70e5b465a2b77c7a7c3d868736d302e29aec
• https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.12.14

• Use of uninitialized resource in Linux kernel time
• Ubuntu update for linux-oem-6.11
• Ubuntu update for linux
• Ubuntu update for linux-azure
• Ubuntu update for linux-realtime