# CVE-2026-74573: linux: In the Linux kernel, the following vulnerability has been resolved:  iommu/arm-smmu-v3-iommufd: Require exactly one S...

CVE-2026-74573 is fixed in linux on 1 platform by DEBIAN-CVE-2026-74573 (version 7.1.8-1), released August 16, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-74573
- Priority: Urgent
- CVSS: 9.3 (critical)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 15, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  iommu/arm-smmu-v3-iommufd: Require exactly one Stream ID for a vDEVICE  arm_vsmmu_vsid_to_sid() maps a guest's vSID to a single physical Stream ID taken from master->streams[0], assuming a device has exactly one stream. A device with several streams gets only its first one mapped, so a guest vSID invalidation cannot reach the others' ATC and IOTLB entries; a device with none makes master->streams a ZERO_SIZE_PTR, read out of bounds.  Add an arm_vsmmu_vdevice_init() op to reject the vDEVICE with -EOPNOTSUPP when master->num_streams is not one, rather than mapping it silently.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.1.8-1 | [DEBIAN-CVE-2026-74573](https://patchblox.com/security/data/fix/linux/debian-cve-2026-74573.md) | Aug 16, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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