CVE-2026-74691

Peer-channel shutdown via reversed DMA teardown

Published Aug 22, 2026 · Updated Aug 25, 2026

Denial of service in Linux allows physically proximate attackers to disable a Thunderbolt XDomain peer through session teardown. tbnet_tear_down() stops the DMA rings and frees their buffers before disabling the paths, leaving in-flight descriptors unable to drain while callers report success. A peer on the same direct Thunderbolt/USB4 link can send TBIP_LOGOUT without authentication; repeated teardown can disable the control channel until a power cycle on routers that retain stale descriptors.

CVSS severity8.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux allows physically proximate attackers to disable a Thunderbolt XDomain peer through session teardown. tbnet_tear_down() stops the DMA rings and frees their buffers before disabling the paths, leaving in-flight descriptors unable to drain while callers report success. A peer on the same direct Thunderbolt/USB4 link can send TBIP_LOGOUT without authentication; repeated teardown can disable the control channel until a power cycle on routers that retain stale descriptors.

The record

CVE
CVE-2026-74691
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=4.15
  2. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <0da9a6d27155ad072dd76db8cd637feead99a0e0
  3. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <103a9b663ac1cacb8465aeff18f84a247154a562
  4. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <4dd71cb0d23d40cb58fe4261c7bd183dca66caa0
  5. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <68bf02b6b4ad3f748c6db71fd77b6c0402d252f4
  6. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <7cce39109206bc5497e0953806563644b88bfc44
  7. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <9a482b2b117e5fa656b6d24fc01799e8ac2d4368
  8. Affected versionversion=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <b5a21615f627c48dafaa6ef82a34a5b97a4352aa

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.15; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <0da9a6d27155ad072dd76db8cd637feead99a0e0; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <103a9b663ac1cacb8465aeff18f84a247154a562; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <4dd71cb0d23d40cb58fe4261c7bd183dca66caa0; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <68bf02b6b4ad3f748c6db71fd77b6c0402d252f4; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <7cce39109206bc5497e0953806563644b88bfc44; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <9a482b2b117e5fa656b6d24fc01799e8ac2d4368; version=e69b6c02b4c3b8d03be7136f90dd9551ad5a5a5e <b5a21615f627c48dafaa6ef82a34a5b97a4352aa

Published CVSS scores

8.8Linux Kernel CVE TeamCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/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.

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No observations available

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

Weakness, pattern, technique

T1499Endpoint Denial of Service

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

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Your stack

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