CVE-2026-89732

Gadget teardown hang via ep0 mutex retention

Published Sep 11, 2026 · Updated Sep 11, 2026

Denial of service in Linux 2.6.35 and affected Git revisions allows local users to hang USB gadget teardown through repeated FunctionFS ep0 reads. ffs_ep0_read sleeps while retaining ffs->mutex, so functionfs_unbind blocks when it needs the same mutex to tear down ep0req. Triggering the hang requires an active FunctionFS gadget, a daemon that immediately rereads ep0 after an unbind event, and concurrent configfs teardown.

CVSS severityUnavailable
Unscored
EPSS probability0.23%
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 2.6.35 and affected Git revisions allows local users to hang USB gadget teardown through repeated FunctionFS ep0 reads. ffs_ep0_read sleeps while retaining ffs->mutex, so functionfs_unbind blocks when it needs the same mutex to tear down ep0req. Triggering the hang requires an active FunctionFS gadget, a daemon that immediately rereads ep0 after an unbind event, and concurrent configfs teardown.

The record

CVE
CVE-2026-89732
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=2.6.35
  2. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <34e88f53614640b59039a46717fb6142e9871022
  3. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <569dd7e5dcffe1e1c6b26ca2cd3be57eb433e082
  4. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <eac233e63f9db82ba874e3cccafaafab162999e0
  5. Affected versionversion=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <fd20cc68bbdb5620696ac108e8f2efd180fe2c1a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.35; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <34e88f53614640b59039a46717fb6142e9871022; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <569dd7e5dcffe1e1c6b26ca2cd3be57eb433e082; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <eac233e63f9db82ba874e3cccafaafab162999e0; version=ddf8abd2599491cbad959c700b90ba72a5dce8d0 <fd20cc68bbdb5620696ac108e8f2efd180fe2c1a

Published CVSS scores

No CVSS assessment is available in this record.

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

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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