CVE-2025-40139

Local kernel compromise via SMC route use-after-free

Published Nov 12, 2025 · Updated Sep 2, 2026

Use-after-free in Linux kernel SMC allows local users to read or corrupt kernel memory via concurrent socket connections. smc_clc_prfx_set() dereferences a cached route's network device outside RCU or RTNL protection while another thread can delete and reclaim that device. A low-privileged local user can drive both sides of the race through AF_SMC connect calls and a user namespace, causing memory disclosure or corruption, a kernel panic, or a CPU hang.

CVSS severity7.8
High
EPSS probability0.15%
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 Linux kernel SMC allows local users to read or corrupt kernel memory via concurrent socket connections. smc_clc_prfx_set() dereferences a cached route's network device outside RCU or RTNL protection while another thread can delete and reclaim that device. A low-privileged local user can drive both sides of the race through AF_SMC connect calls and a user namespace, causing memory disclosure or corruption, a kernel panic, or a CPU hang.

The record

CVE
CVE-2025-40139
Published
Nov 12, 2025
Updated
Sep 2, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1068
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Nov 12, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 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=4.11
  2. Affected versionversion=a046d57da19f812216f393e7c535f5858f793ac3 <0736993bfe5c7a9c744ae3fac62d769dfdae54e1
  3. Affected versionversion=a046d57da19f812216f393e7c535f5858f793ac3 <5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde
  4. Affected versionversion=a046d57da19f812216f393e7c535f5858f793ac3 <80d1fd39f4e37d836655e9f7ffccaf78925049bf
  5. Affected versionversion=a046d57da19f812216f393e7c535f5858f793ac3 <935d783e5de9b64587f3adb25641dd8385e64ddb
  6. Affected versionversion=a046d57da19f812216f393e7c535f5858f793ac3 <956c57daba55cf9ed25d9f2512883b8a1a927599

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=4.11; version=a046d57da19f812216f393e7c535f5858f793ac3 <0736993bfe5c7a9c744ae3fac62d769dfdae54e1; version=a046d57da19f812216f393e7c535f5858f793ac3 <5a2fccc4b32c13ddde3676f9e15e1a9baa7d6fde; version=a046d57da19f812216f393e7c535f5858f793ac3 <80d1fd39f4e37d836655e9f7ffccaf78925049bf; version=a046d57da19f812216f393e7c535f5858f793ac3 <935d783e5de9b64587f3adb25641dd8385e64ddb; version=a046d57da19f812216f393e7c535f5858f793ac3 <956c57daba55cf9ed25d9f2512883b8a1a927599

Published CVSS scores

7.8Linux kernel CNACVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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