A security problem was found in the Linux kernel used by Ubuntu that could let someone with local access bypass memory protections or increase their privileges. It mainly affects some Arm processors where certain hardware behavior might allow memory writes to happen even after permission was revoked. Additionally, many other security issues were found and fixed across many parts of the Linux kernel. Users should update their systems and reboot to apply the fixes.
Published 7/9/2026, 8:57:53 amVerified 7/9/2026, 10:18:31 pmRevision 1
In plain language
What this advisory means
A security problem was found in the Linux kernel used by Ubuntu that could let someone with local access bypass memory protections or increase their privileges. It mainly affects some Arm processors where certain hardware behavior might allow memory writes to happen even after permission was revoked. Additionally, many other security issues were found and fixed across many parts of the Linux kernel. Users should update their systems and reboot to apply the fixes.
Technical explanation
How the issue affects the environment
The vulnerability (CVE-2025-10263) involves some Arm processors performing a broadcast Translation Lookaside Buffer (TLB) invalidation before memory writes through the invalidated translation are globally observed. This timing issue allows a local attacker to write to memory after permissions have been revoked, thereby bypassing memory protections or escalating privileges. Moreover, numerous additional security flaws were identified and corrected across various kernel subsystems and architectures, including ARM64, ARM32, x86, RISC-V, networking, cryptographic APIs, device drivers, filesystems, and security modules. The update includes changes requiring recompilation of third-party kernel modules due to an ABI change. A system reboot after updating is necessary to activate these changes.
Operational impact
Why teams should care
Exploitation of these vulnerabilities could lead to unauthorized memory access, privilege escalation, or system compromise. This puts Ubuntu systems at risk of unauthorized control, data breaches, or service disruption. Organizations running affected Ubuntu Linux kernels should promptly update and reboot their systems to maintain security and operational integrity.
Immediate action
Update your Ubuntu Linux kernel packages to the latest available versions and then reboot your system to apply the changes fully. Note that because of an Application Binary Interface (ABI) change in the kernel update, all third-party kernel modules will need to be recompiled and reinstalled to maintain compatibility.
Affected and fixed releases
Affected versionsConfirm in the official vendor advisory
Fixed versionsConfirm in the official vendor advisory
Temporary risk reduction
The official source does not specify any workaround. The recommended action is to apply the update and reboot the system.
Evidence and validation checklist
The source confirms the ARM processor vulnerability involving incorrect TLB invalidation timing (CVE-2025-10263).
Many other kernel subsystems were found vulnerable and have fixes available as per the source, including architectures and drivers.
Kernel ABI changes require recompilation of modules.
Updating and rebooting is necessary to apply changes.
Authoritative reference
Ubuntu Security Notices
QCS detected and normalized this record from the official source. Vendor guidance remains authoritative.
