CVE-2026-90215Hinoki check available

Resource leak via unbalanced busy-detach device reference

Published Sep 17, 2026 · Updated Sep 17, 2026

A reference leak in Linux 6.9 UBI allows local users to retain device objects through busy MTD detach requests. In drivers/mtd/ubi/build.c, ubi_detach_mtd_dev() obtains a device reference but its busy return path decrements only ubi->ref_count, preventing object release after a later detach. The control ioctl requires CAP_SYS_RESOURCE and an attached, busy UBI device; the documented consequence is resource retention, not a demonstrated crash or reboot.

CVSS severity2.3
Low
EPSS probability0.17%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

A reference leak in Linux 6.9 UBI allows local users to retain device objects through busy MTD detach requests. In drivers/mtd/ubi/build.c, ubi_detach_mtd_dev() obtains a device reference but its busy return path decrements only ubi->ref_count, preventing object release after a later detach. The control ioctl requires CAP_SYS_RESOURCE and an attached, busy UBI device; the documented consequence is resource retention, not a demonstrated crash or reboot.

The record

CVE
CVE-2026-90215
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-772, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=6.9
  2. Affected versionversion=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <31dd710cd84d5dd63c49f640d3a9f36c9699ca95
  3. Affected versionversion=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <851c5e9a829d56cb0982965f07ef8966a6722884
  4. Affected versionversion=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <87812858c4c8df979cb70bcd0040b925a543df6f
  5. Affected versionversion=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <e065960366b55ab21e6c643c30dec2a41451900b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=6.9; version=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <31dd710cd84d5dd63c49f640d3a9f36c9699ca95; version=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <851c5e9a829d56cb0982965f07ef8966a6722884; version=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <87812858c4c8df979cb70bcd0040b925a543df6f; version=7e84c961b2eb062d2f47037dcca52dcd1d3615b5 <e065960366b55ab21e6c643c30dec2a41451900b

Published CVSS scores

5.6TenableAV:L/AC:L/Au:N/C:P/I:N/A:C
6.6Tenable NessusAV:L/AC:L/Au:N/C:C/I:N/A:C
2.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Tenable NessusCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.1Tenable NessusCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:U/RC:C
5.5TenableCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-772Missing Release of Resource after Effective Lifetime
T1499.004Application 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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