CVE-2025-40258Network attack vector

Kernel use-after-free via delayed socket reference acquisition

Published Dec 4, 2025 · Updated Aug 5, 2026

A Linux MPTCP scheduler race allows attackers to trigger a socket use-after-free in Linux 5.7 and RUGGEDCOM RST2428P before V4.0. mptcp_schedule_work() queues work before taking the socket reference, so mptcp_worker() can finish and release the socket before sock_hold() increments its reference count. The upstream CNA rates the path as remote and unauthenticated, while Siemens rates its switch exposure as local and low-privileged; the demonstrated result is a kernel memory-safety failure.

CVSS severity9.8
Critical
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A Linux MPTCP scheduler race allows attackers to trigger a socket use-after-free in Linux 5.7 and RUGGEDCOM RST2428P before V4.0. mptcp_schedule_work() queues work before taking the socket reference, so mptcp_worker() can finish and release the socket before sock_hold() increments its reference count. The upstream CNA rates the path as remote and unauthenticated, while Siemens rates its switch exposure as local and low-privileged; the demonstrated result is a kernel memory-safety failure.

The record

CVE
CVE-2025-40258
Published
Dec 4, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-362, T1068
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=3b1d6210a9577369103330b0d802b0bf74b65e7f <035bca3f017ee9dea3a5a756e77a6f7138cc6eea
  2. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <3fc7723ed01d1130d4bf7063c50e0af60ecccbb4
  3. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <8f9ba1a99a89feef9b5867c15a0141a97e893309
  4. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <99908e2d601236842d705d5fd04fb349577316f5
  5. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <ac28dfddedf6f209190950fc71bcff65ec4ab47b
  6. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <db4f7968a75250ca6c4ed70d0a78beabb2dcee18
  7. Affected versionversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <f865e6595acf33083168db76921e66ace8bf0e5b
  8. Affected versionversion=5.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3b1d6210a9577369103330b0d802b0bf74b65e7f <035bca3f017ee9dea3a5a756e77a6f7138cc6eea; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <3fc7723ed01d1130d4bf7063c50e0af60ecccbb4; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <8f9ba1a99a89feef9b5867c15a0141a97e893309; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <99908e2d601236842d705d5fd04fb349577316f5; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <ac28dfddedf6f209190950fc71bcff65ec4ab47b; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <db4f7968a75250ca6c4ed70d0a78beabb2dcee18; version=3b1d6210a9577369103330b0d802b0bf74b65e7f <f865e6595acf33083168db76921e66ace8bf0e5b; version=5.7
Siemens · RUGGEDCOM RST2428Pversion=0 <V4.0

Published CVSS scores

7.8Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
9.8Linux kernel CNACVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Oracle LinuxCVSS:3.1/AV:L/AC:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
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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