USN-8889-1: fixes across OEM Linux kernel subsystems and an AMD RMP check flaw

Notice USN-8889-1, published on October 6, 2026 in the Ubuntu Security feed, covers vulnerabilities in OEM Linux kernels. The text received is a machine translation of the original content, so verify technical terms against the official source before acting. The notice describes two areas. The first is a flaw in some AMD processors that did not correctly perform Reverse Map Table (RMP) checks when the IOMMU accessed certain host buffers. According to the notice, a local attacker with access to the hypervisor could possibly use this issue to trigger an out-of-bounds condition and compromise the integrity of SEV-SNP guest memory, identified as CVE-2023-20585. The second area is several security issues in the Linux kernel that, according to the notice, could possibly be used to compromise the system. The update fixes flaws across a long list of subsystems, including ARM64, ARM32, MIPS, x86, PowerPC, RISC-V and S390 architectures; NVDIMM, Cryptographic API, IOMMU, PCI, NVMe, network drivers, GPU drivers, Bluetooth, TPM, I2C and many other hardware drivers. For administrators of servers and workstations running OEM kernels, the recommended step is to check whether the installed version appears in the vendor or distribution fix list, apply the update and reboot when required. To verify details, consult the notice itself on the Ubuntu Security site, which contains the full list and affected versions.