CVE-2026-90325

Kernel use-after-free via blk-cgroup deletion race

Published Sep 17, 2026 · Updated Sep 18, 2026

Use-after-free in affected Linux kernel versions allows local users to trigger invalid kernel memory access while switching I/O schedulers. In block/blk-cgroup.c, blkcg_activate_policy() can take a reference to a blkg after concurrent deletion has unhashed and freed its policy data, causing a second RCU release. Reachability requires permission to change a block device's scheduler and concurrent blkcg deletion; the published record establishes the use-after-free but no further consequence.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in affected Linux kernel versions allows local users to trigger invalid kernel memory access while switching I/O schedulers. In block/blk-cgroup.c, blkcg_activate_policy() can take a reference to a blkg after concurrent deletion has unhashed and freed its policy data, causing a second RCU release. Reachability requires permission to change a block device's scheduler and concurrent blkcg deletion; the published record establishes the use-after-free but no further consequence.

The record

CVE
CVE-2026-90325
Published
Sep 17, 2026
Updated
Sep 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 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=6.1.16 <6.1.17
  2. Affected versionversion=6.2.3 <6.2.4
  3. Affected versionversion=6.3
  4. Affected versionversion=81c1188905f88b77743d1fdeeedfc8cb7b67787d <b5dae1cd0d8368b4338430ff93403df67f0b8bcc
  5. Affected versionversion=bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a <083b58373463a6e5ee60ecb135269348f68ad7df
  6. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <1a267295b1ea6a6477963f3fda84adfecd48fcad
  7. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <3d8c3da95c75a4d312e272fc7b4076dd3ba9115c
  8. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <5e9220389920f33b6a804d50c548cd0cd1b04634
  9. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d
  10. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <d8c872901e6459339374e9eea80aa919176c2ccd

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=6.1.16 <6.1.17; version=6.2.3 <6.2.4; version=6.3; version=81c1188905f88b77743d1fdeeedfc8cb7b67787d <b5dae1cd0d8368b4338430ff93403df67f0b8bcc; version=bfe46d2efe46c5c952f982e2ca94fe2ec5e58e2a <083b58373463a6e5ee60ecb135269348f68ad7df; version=f1c006f1c6850c14040f8337753a63119bba39b9 <1a267295b1ea6a6477963f3fda84adfecd48fcad; version=f1c006f1c6850c14040f8337753a63119bba39b9 <3d8c3da95c75a4d312e272fc7b4076dd3ba9115c; version=f1c006f1c6850c14040f8337753a63119bba39b9 <5e9220389920f33b6a804d50c548cd0cd1b04634; version=f1c006f1c6850c14040f8337753a63119bba39b9 <7337d012ca3fc3a6a2d1c8e2a19c6d97c38b410d; version=f1c006f1c6850c14040f8337753a63119bba39b9 <d8c872901e6459339374e9eea80aa919176c2ccd

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.

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
PrivilegesUnavailable
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

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Your stack

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