CVE-2026-98525Hinoki check available

Unauthorized tag use via unchecked socket ownership

Published Oct 18, 2026 · Updated Oct 18, 2026

Linux MCTP tag isolation failure allows local users to transmit messages using another socket's preallocated tag. In net/mctp/route.c, mctp_lookup_prealloc_tag() searches namespace-wide tags without verifying ownership by the sending socket. Exploitation requires permission to send MCTP messages and a matching preallocated tag in the same network namespace; the demonstrated consequence is cross-socket tag use, not code execution.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Linux MCTP tag isolation failure allows local users to transmit messages using another socket's preallocated tag. In net/mctp/route.c, mctp_lookup_prealloc_tag() searches namespace-wide tags without verifying ownership by the sending socket. Exploitation requires permission to send MCTP messages and a matching preallocated tag in the same network namespace; the demonstrated consequence is cross-socket tag use, not code execution.

The record

CVE
CVE-2026-98525
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 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=5.18
  2. Affected versionversion=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <09299addab11857e92eca55cd8ef3350b927c90c
  3. Affected versionversion=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <26cc0e69cce062cd3aa6fae33074684669c35a71
  4. Affected versionversion=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <e35cb500dd14882f8dee61783fccd1823fd3ab0d
  5. Affected versionversion=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <f178300e2f56ca9ec2a3a0090608730bbee0af7b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.18; version=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <09299addab11857e92eca55cd8ef3350b927c90c; version=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <26cc0e69cce062cd3aa6fae33074684669c35a71; version=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <e35cb500dd14882f8dee61783fccd1823fd3ab0d; version=63ed1aab3d40aa61aaa66819bdce9377ac7f40fa <f178300e2f56ca9ec2a3a0090608730bbee0af7b

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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