Ubuntu USN-8663-1 Security Advisory: Linux Kernel Privilege Escalation Fixes

Vulnerability Overview Vulnerability ID: USN-8663-1 Publication Date: 20 August 2026 Description: Certain AMD Zen 2 processors were found to incorrectly isolate shared resources within the operation cache. A local attacker may exploit this issue to execute corrupted instructions at higher privilege levels, leading to privilege escalation (CVE-2023-54511). Additionally, multiple security issues were discovered in the Linux kernel, which attackers could exploit to compromise the system. Affected Systems Affected Systems: - x86 platform drivers - Cryptographic API - PSP security protocol - ARM32 architecture - ARM64 architecture - MIPS architecture - PowerPC architecture - RISC-V architecture - S390 architecture - User Mode Linux (UML) - x86 architecture - Block layer subsystem - Intel NPU drivers - Compute Acceleration Framework - ACPI drivers - Auxiliary drivers Remediation Update Notes: - A system restart is required after applying standard system updates to implement all necessary changes. - Due to unavoidable ABI changes, the kernel update has been assigned a new version number, requiring all third-party kernel modules to be recompiled and reinstalled. Standard system upgrades will perform this automatically unless the standard kernel meta-packages (such as , , , ) are manually removed. Fixed Versions: - Ubuntu 26.04 LTS (resolute): - linux-image-7.0.0-1016-nvidia – 7.0.0-1016.16 - linux-image-7.0.0-1016-nvidia-64k – 7.0.0-1016.16 - linux-image-nvidia – 7.0.0-1016.16 - linux-image-nvidia-64k – 7.0.0-1016.16 - linux-image-nvidia-7.0 – 7.0.0-1016.16 - linux-image-nvidia-7.0 – 7.0.0-1016.16 - Ubuntu 24.04 LTS (noble): - linux-image-7.0.0-1016-nvidia – 7.0.0-1016.16-24.04.1 - linux-image-7.0.0-1016-nvidia-64k – 7.0.0-1016.16-24.04.1 - linux-image-nvidia-64k-7.0 – 7.0.0-1016.16-24.04.1 - linux-image-nvidia-7.0 – 7.0.0-1016.16-24.04.1 References CVE-2026-64528 CVE-2026-64527 CVE-2026-64526 CVE-2026-64525 CVE-2026-64524 CVE-2026-64523 CVE-2026-64522 CVE-2026-64521 CVE-2026-64519 CVE-2026-64518 Related Notices USN-8664-1 USN-8662-1 USN-8661-1 USN-8660-1 USN-8658-1 USN-8656-1 USN-8646-1 USN-8645-1 USN-8644-1 USN-8644-2 Additional Information Reduce Security Risk: Ubuntu Pro offers ten years of security coverage for packages in more than 25,000 main and universe repositories, available free for up to five machines. Code Blocks No POC code or exploit code is included in the page.

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Ubuntu USN-8663-1 Security Advisory: Linux Kernel Privilege Escalation Fixes

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