CVE-2026-90326Hinoki check available

Local privilege escalation via blk-cgroup lifetime race

Published Sep 17, 2026 · Updated Sep 18, 2026

Use-after-free in affected Linux kernel releases allows local users to corrupt kernel memory through a blk-cgroup race. blkcg_activate_policy() can traverse a blkg whose policy data blkg_free_workfn() freed before removing the blkg from q->blkg_list, causing stale reads, writes, or a double free. A low-privileged owner of a delegated cgroup-v2 subtree can race io.max or io.latency writes with child-cgroup removal, enabling kernel compromise or a host crash.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in affected Linux kernel releases allows local users to corrupt kernel memory through a blk-cgroup race. blkcg_activate_policy() can traverse a blkg whose policy data blkg_free_workfn() freed before removing the blkg from q->blkg_list, causing stale reads, writes, or a double free. A low-privileged owner of a delegated cgroup-v2 subtree can race io.max or io.latency writes with child-cgroup removal, enabling kernel compromise or a host crash.

The record

CVE
CVE-2026-90326
Published
Sep 17, 2026
Updated
Sep 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499, T1068
Attack vector
local
Privileges
authenticated

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 <2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd
  7. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <5313d4d41739b0cb63000747c97bb1217ac45f3e
  8. Affected versionversion=f1c006f1c6850c14040f8337753a63119bba39b9 <ac34e655dffa74349d885a43d098115336f53842

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

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 <2cf9f50a38c1839e549a08e22aa35e8d69e2c8fd; version=f1c006f1c6850c14040f8337753a63119bba39b9 <5313d4d41739b0cb63000747c97bb1217ac45f3e; version=f1c006f1c6850c14040f8337753a63119bba39b9 <ac34e655dffa74349d885a43d098115336f53842

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service
T1068Exploitation for Privilege Escalation

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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