Cloudanix VulnDB

CVE-2025-71202

Medium · 5.5

CVSS

5.5

EPSS

0.2%

Published

Feb 14, 2026

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A flaw in Linux kernel memory handling on certain x86 systems could let local users crash the machine by freeing memory that the hardware still thinks is in use.

Exploitation
Local Privilege
Attacker needs
Low Privilege
Complexity
Low
Impact
Denial Of Service
Component
OS kernel
Class
Use After Free
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

The vulnerability is a use-after-free in the IOMMU subsystem on x86 where stale IOTLB paging cache entries for kernel address space are not invalidated before vfree() frees and reuses kernel page table pages, allowing references to freed memory.

Why it matters to the business

Unprivileged local users can trigger denial of service or system instability on affected Linux kernels that enable SVA with IOMMU; the issue is common via vfree and requires prompt patching to maintain kernel stability across server and desktop deployments.

How an attack unfolds

An attacker with local unprivileged access triggers repeated vfree operations on kernel-managed memory regions; because the IOMMU is not notified to flush stale IOTLB entries, the freed page table pages can be reused while IOMMU hardware still holds valid translations, resulting in use-after-free access to kernel memory.

How to fix it

Upgrade the Linux kernel to the commit 9f0a7ab700f8620e433b05c57fbd26c92ea186d9 or later stable releases that include the new IOMMU interface for flushing IOTLB entries before freeing kernel page table pages; enable the interface on x86 systems using combined page tables.

How to confirm the fix worked

Confirm the running kernel contains commit 9f0a7ab700f8620e433b05c57fbd26c92ea186d9, verify IOMMU SVA initialization logs show the new flush interface is active, and test that vfree operations no longer produce use-after-free warnings in kernel memory debugging tools.

Typical attack path

  1. Obtain local unprivileged shell on x86 Linux system with IOMMU SVA enabled
  2. Trigger vfree of kernel address space pages through normal memory operations
  3. Reuse the freed page table pages before IOMMU IOTLB invalidation occurs
  4. Cause IOMMU to access stale translations leading to use-after-free

How to detect it

Review kernel logs for use-after-free warnings or IOMMU page table faults around vfree calls; inspect dmesg and audit logs for IOMMU invalidation failures prior to the fix commit; no specific post-exploitation artifacts are expected beyond generic kernel crashes.

What your security team should do

  • Prioritize kernel upgrades to the fixed commit within standard patch windows for all x86 systems using IOMMU
  • Monitor EPSS trend and re-evaluate if public exploits appear
  • Enable kernel memory debugging and IOMMU logging on test systems to validate the fix

The record

In the Linux kernel, the following vulnerability has been resolved: iommu/sva: invalidate stale IOTLB entries for kernel address space Introduce a new IOMMU interface to flush IOTLB paging cache entries for the CPU kernel address space. This interface is invoked from the x86 architecture code that manages combined user and kernel page tables, specifically before any kernel page table page is freed and reused. This addresses the main issue with vfree() which is a common occurrence and can be triggered by unprivileged users. While this resolves the primary problem, it doesn't address some extremely rare case related to memory unplug of memory that was present as reserved memory at boot, which cannot be triggered by unprivileged users. The discussion can be found at the link below. Enable SVA on x86 architecture since the IOMMU can now receive notification to flush the paging cache before freeing the CPU kernel page table pages.

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 4.4.0 6.18.7

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