CVE-2026-97566Hinoki check available

Kernel warning via stale ADD_ADDR announcement

Published Sep 25, 2026 · Updated Sep 25, 2026

Improper MPTCP state cleanup in Linux allows local users to trigger a kernel warning through endpoint reconfiguration. The ID0 removal path leaves a pending ADD_ADDR entry in anno_list, so later ID0 reselection reaches WARN_ON_ONCE in mptcp_pm_announced_alloc. Reaching the condition requires privileged MPTCP endpoint operations; the upstream report documents a warning but no crash, privilege gain, or data exposure.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Improper MPTCP state cleanup in Linux allows local users to trigger a kernel warning through endpoint reconfiguration. The ID0 removal path leaves a pending ADD_ADDR entry in anno_list, so later ID0 reselection reaches WARN_ON_ONCE in mptcp_pm_announced_alloc. Reaching the condition requires privileged MPTCP endpoint operations; the upstream report documents a warning but no crash, privilege gain, or data exposure.

The record

CVE
CVE-2026-97566
Published
Sep 25, 2026
Updated
Sep 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 25, 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=5.13
  2. Affected versionversion=740d798e8767d8a449902b1a1bbc70facfce19b5 <2ac7d6e620764f1fc79eb4edd3610a7a661981ca
  3. Affected versionversion=740d798e8767d8a449902b1a1bbc70facfce19b5 <545616b4e7325be3c61fc082538cb06d14f7b1db
  4. Affected versionversion=740d798e8767d8a449902b1a1bbc70facfce19b5 <d4a67a880654e1bfe318a31bea0bdbb026a09ade

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=740d798e8767d8a449902b1a1bbc70facfce19b5 <2ac7d6e620764f1fc79eb4edd3610a7a661981ca; version=740d798e8767d8a449902b1a1bbc70facfce19b5 <545616b4e7325be3c61fc082538cb06d14f7b1db; version=740d798e8767d8a449902b1a1bbc70facfce19b5 <d4a67a880654e1bfe318a31bea0bdbb026a09ade

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
Privilegesadmin
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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