CVE-2026-90315
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]
Executive briefing
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Evidence confidence: Not assessed Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:Not supplied
No CVSS vector is currently available in the source record.
Technical explanation & impact
Technical root-cause details are not available in the current source record.
Assess the impact using the published CVSS metrics and the affected vendor component.
Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
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Vendor advisories, patches & exploit references
No external references are currently supplied in the CVE record.