CVE-2026-53057

What it actually does

This is a Linux kernel RISC-V IOMMU correctness flaw: after Device Directory Table (DDT) or Process Directory Table (PDT) entries are updated, the kernel failed to perform the required IOTINVAL invalidation of IOMMU translation and context caches. As a result, the IOMMU may continue using stale device or process translation state after permissions, mappings, or ownership have changed. In practical terms, this can weaken DMA isolation, allowing a device to operate with outdated address-translation or access-control information. Depending on platform configuration and attacker control over a device, driver, VFIO assignment, or virtualized I/O path, this could contribute to unauthorized memory access, data corruption, denial of service, or local privilege-boundary bypass on affected RISC-V systems.

Why it matters to the business

The primary business risk is loss of hardware-enforced memory isolation on affected RISC-V Linux systems. Systems using RISC-V IOMMU features for device assignment, virtualization, sandboxing, or DMA protection may be exposed to memory corruption or unauthorized access between devices, workloads, or guests. Current public exploitation likelihood appears low: EPSS is very low, there is no known CISA KEV listing, no ransomware association, and no public exploit maturity is indicated. However, because the issue is in kernel-level device isolation logic, organizations running production RISC-V Linux infrastructure should still treat remediation as important during normal kernel maintenance cycles, especially where untrusted workloads, passthrough devices, or multi-tenant virtualization are present.

How an attack unfolds

An attacker would need a path to influence DMA-capable device behavior or trigger changes to RISC-V IOMMU DDT/PDT mappings, such as through a malicious or compromised device, a vulnerable driver, a VFIO/device-passthrough scenario, or a local workload with access to device-management interfaces. The attacker attempts to cause the kernel to update IOMMU directory entries while the IOMMU continues to use cached stale translations or context state because the required invalidation was not issued. If successful, DMA operations may proceed under old permissions or mappings after they should have been revoked or changed. This could allow reads or writes to memory outside the attacker’s intended boundary, potentially leading to information disclosure, memory corruption, guest-to-host or guest-to-guest isolation impact, or system instability. No public exploitation or named threat actor activity is currently indicated for this vulnerability.

How to fix it

Upgrade to a Linux kernel build that includes the RISC-V IOMMU fix adding IOTINVAL invalidation after DDT/PDT updates. No specific affected product list or fixed package versions were provided in the input, so remediation should be performed through the relevant Linux distribution, kernel vendor, appliance vendor, or platform maintainer advisory. Where immediate patching is not possible, reduce exposure by disabling unused DMA-capable devices, avoiding assignment of untrusted devices to guests or workloads, restricting VFIO/device-passthrough use, limiting local administrative/device-management access, and ensuring IOMMU/firmware configuration follows vendor guidance. Mitigations should be considered risk-reducing only; the durable fix is a patched kernel.

How to confirm the fix worked

Confirm the running kernel version and vendor package build include the upstream fix for the RISC-V IOMMU IOTINVAL handling after DDT/PDT updates. Validate by checking distribution security advisories, kernel changelogs, or source/package contents for the RISC-V IOMMU change that adds invalidation after directory entry updates. On source-based builds, verify the patched code path includes the new invalidation call after DDT/PDT updates. Reboot into the updated kernel and confirm the active kernel is the fixed version, not merely installed. For exposure validation, inventory RISC-V systems, determine whether RISC-V IOMMU support is enabled, and identify systems using virtualization, VFIO, device passthrough, or other DMA-sensitive workloads.

Typical attack path

1. Identify a RISC-V Linux system using an affected kernel with RISC-V IOMMU enabled.
2. Obtain local code execution, control over a DMA-capable peripheral, access to a device-passthrough interface, or influence over a driver path that changes IOMMU mappings.
3. Trigger DDT or PDT entry updates such as device context changes, mapping changes, permission changes, or teardown/reassignment events.
4. Race or sequence DMA operations so the IOMMU continues using stale cached translation or context state.
5. Use stale access to read or write memory that should no longer be accessible, causing data exposure, corruption, privilege-boundary bypass, or denial of service.

How to detect it

There is no reliable CVE-specific exploit indicator for this kernel logic flaw, and successful abuse may leave little direct evidence beyond secondary effects. Detection should focus on systems where exploitation is plausible: RISC-V Linux hosts with IOMMU enabled, DMA-capable devices, virtualization, VFIO, or device passthrough. Review kernel logs, hypervisor logs, crash dumps, and audit records for unexplained IOMMU faults, DMA mapping failures, device reset storms, kernel oops/panic events, memory corruption symptoms, or abnormal behavior during device assignment, reassignment, or teardown. Investigate unusual access by local users or workloads to device-management interfaces, VFIO device nodes, PCI device binding/unbinding, or privileged driver operations. If named threat actor or campaign intelligence later emerges, correlate that activity with local privilege escalation attempts and device-management events on RISC-V systems.

What your security team should do

• Inventory RISC-V Linux systems and prioritize those using IOMMU-dependent isolation, virtualization, VFIO, device passthrough, or DMA-capable accelerators.
• Apply vendor-provided kernel updates that include the RISC-V IOMMU IOTINVAL fix, prioritizing multi-tenant or untrusted-workload systems first.
• If patching is delayed, temporarily restrict device passthrough and access to DMA-capable devices, especially for untrusted users or workloads.
• Review kernel, hypervisor, and system logs for unexplained IOMMU faults, DMA errors, kernel oops events, or crashes around device assignment, teardown, or mapping changes.
• Track vendor advisories for exact fixed versions and update golden images, embedded builds, and appliance firmware where applicable.
• Because public exploitation signals are currently low, handle as a scheduled but important kernel isolation update rather than an emergency internet-facing remote-code-execution event.