CVE-2026-74573

Guest-triggered out-of-bounds read via unchecked Stream ID count

Published Aug 15, 2026 · Updated Aug 15, 2026

Out-of-bounds read in the ARM SMMUv3 iommufd code in Linux 6.13 allows guest OS users to trigger an invalid kernel-memory access. arm_vsmmu_vsid_to_sid() always reads master->streams[0] and maps only that entry, without first requiring exactly one physical Stream ID. Reachability requires an assigned ARM SMMUv3 device backed by zero or multiple Stream IDs; zero triggers the invalid read, while multiple IDs leave other ATC and IOTLB entries stale after guest invalidation.

CVSS severity9.3
Critical
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Out-of-bounds read in the ARM SMMUv3 iommufd code in Linux 6.13 allows guest OS users to trigger an invalid kernel-memory access. arm_vsmmu_vsid_to_sid() always reads master->streams[0] and maps only that entry, without first requiring exactly one physical Stream ID. Reachability requires an assigned ARM SMMUv3 device backed by zero or multiple Stream IDs; zero triggers the invalid read, while multiple IDs leave other ATC and IOTLB entries stale after guest invalidation.

The record

CVE
CVE-2026-74573
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.13
  2. Affected versionversion=d68beb276ba26cec47350a6d468e967673ee0c56 <0acbc621341aca4eb94d9c2f43e1ab273ff088f0
  3. Affected versionversion=d68beb276ba26cec47350a6d468e967673ee0c56 <3808bab5d95ae79e333e11f6a73d178e084c645d
  4. Affected versionversion=d68beb276ba26cec47350a6d468e967673ee0c56 <c3b8ee84a965058b41275069d4696f37a8b14bf6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.13; version=d68beb276ba26cec47350a6d468e967673ee0c56 <0acbc621341aca4eb94d9c2f43e1ab273ff088f0; version=d68beb276ba26cec47350a6d468e967673ee0c56 <3808bab5d95ae79e333e11f6a73d178e084c645d; version=d68beb276ba26cec47350a6d468e967673ee0c56 <c3b8ee84a965058b41275069d4696f37a8b14bf6

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
9.3Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo