CVE-2026-89564Public exploitHinoki check available

Kernel panic via stale multicast socket pointer

Published Sep 11, 2026 · Updated Sep 11, 2026

Use-after-free in the Linux kernel allows local users to trigger a stale socket dereference through multicast forwarding. IPv4 and IPv6 retain an unreferenced skb socket association beyond receive-side RCU protection, and sock_pfree later dereferences it after socket destruction. Non-root access to user and network namespaces is sufficient, and the demonstrated consequence is a kernel panic and prolonged service interruption.

CVSS severityUnavailable
Unscored
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in the Linux kernel allows local users to trigger a stale socket dereference through multicast forwarding. IPv4 and IPv6 retain an unreferenced skb socket association beyond receive-side RCU protection, and sock_pfree later dereferences it after socket destruction. Non-root access to user and network namespaces is sufficient, and the demonstrated consequence is a kernel panic and prolonged service interruption.

The record

CVE
CVE-2026-89564
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

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=5.7
  2. Affected versionversion=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce
  3. Affected versionversion=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <e36ce6e78fe3fc3c071a26750783b7ba081ce10d
  4. Affected versionversion=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <f1281d4b99089fbaf0d3579bba62a814ebb4de4d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <a8af6fbac895f057c4b8ff8a2e3fb4c5827fe4ce; version=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <e36ce6e78fe3fc3c071a26750783b7ba081ce10d; version=cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449 <f1281d4b99089fbaf0d3579bba62a814ebb4de4d

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

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

Public exploit references

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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