CVE Catalog

CVE-2026-90315

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, the legacy I/O and memory sysfs handlers did not check security_locked_down(LOCKDOWN_PCI_ACCESS). As a result, root could write arbitrary I/O ports and map legacy I/O and memory spaces even when the kernel was locked down.

Risk Assessment

Even with kernel lockdown enabled, a privileged user can program DMA-capable hardware and modify kernel code, defeating the purpose of the lockdown mechanism.

Recommendation

Update the Linux kernel to a version that adds the lockdown check to pci_write_legacy_io(), pci_mmap_legacy_mem(), and pci_mmap_legacy_io().

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: PCI/sysfs: Add lockdown checks to legacy I/O and memory handlers Currently, the legacy I/O and memory sysfs handlers do not check security_locked_down(LOCKDOWN_PCI_ACCESS), leaving the legacy_io and legacy_mem files unprotected when the kernel is locked down. Commit eb627e17727e ("PCI: Lock down BAR access when the kernel is locked down") added the check to pci_write_config(), pci_mmap_resource(), and pci_write_resource_io() to prevent userspace from programming DMA-capable hardware that could be used to modify kernel code, but did not cover the legacy handlers. As a result, root can still write arbitrary I/O ports and map the legacy I/O and memory spaces while the kernel is locked down, which is the same capability the lockdown is meant to remove. Add the same check to pci_write_legacy_io(), pci_mmap_legacy_mem(), and pci_mmap_legacy_io(). These generic handlers cover both architectures that define HAVE_PCI_LEGACY (such as Alpha and PowerPC). [bhelgaas: add Link]

Vulnerability data from NVD (NIST) · CISA KEV · EPSS