CVE-2022-3977

Local privilege escalation via MCTP tag race

Published Jan 12, 2023 · Updated Apr 8, 2025

Use-after-free in the Linux kernel MCTP subsystem allows local users to crash the system or gain elevated privileges through a race. A race between SIOCMCTPDROPTAG and socket close makes mctp_sk_unhash remove the same tag key twice and release both references, causing a use-after-free. Local users can reach it when MCTP is available; the module is not loaded automatically, and exploitation can crash the host or elevate privileges.

CVSS severity7.8
High
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux kernel MCTP subsystem allows local users to crash the system or gain elevated privileges through a race. A race between SIOCMCTPDROPTAG and socket close makes mctp_sk_unhash remove the same tag key twice and release both references, causing a use-after-free. Local users can reach it when MCTP is available; the module is not loaded automatically, and exploitation can crash the host or elevate privileges.

The record

CVE
CVE-2022-3977
Published
Jan 12, 2023
Updated
Apr 8, 2025
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2025Record 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=Linux kernel 6.1-rc1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Linux kernel 6.1-rc1

Published CVSS scores

7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS: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.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
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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