CVE-2025-68227

Kernel warning via incorrect MPTCP fallback operations

Published Dec 16, 2025 · Updated Dec 16, 2025

Improper protocol fallback in affected Linux kernel releases beginning with 5.7 allows local users to trigger a kernel warning through BPF sockmap use. In net/mptcp/protocol.c, mptcp_fallback_tcp_ops() compares mutable sk_prot state to choose native socket operations after sockmap has replaced that state, so it can assign the wrong sk_socket operations. The path requires server-side MPTCP, a non-MPTCP client SYN, BPF sockmap replacement, and subsequent accept processing; the documented consequence is a warning and incorrect socket operations.

CVSS severityUnavailable
Unscored
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper protocol fallback in affected Linux kernel releases beginning with 5.7 allows local users to trigger a kernel warning through BPF sockmap use. In net/mptcp/protocol.c, mptcp_fallback_tcp_ops() compares mutable sk_prot state to choose native socket operations after sockmap has replaced that state, so it can assign the wrong sk_socket operations. The path requires server-side MPTCP, a non-MPTCP client SYN, BPF sockmap replacement, and subsequent accept processing; the documented consequence is a warning and incorrect socket operations.

The record

CVE
CVE-2025-68227
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 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=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <037cc50589643342d69185b663ecf9d26cce91e8
  2. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00
  3. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <344974ea1a3ca30e4920687b0091bda4438cebdb
  4. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <7ee8f015eb47907745e2070184a8ab1e442ac3c4
  5. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c
  6. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <9b1980b6f23fa30bf12add19f37c7458625099eb
  7. Affected versionversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <c77b3b79a92e3345aa1ee296180d1af4e7031f8f
  8. Affected versionversion=5.7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <037cc50589643342d69185b663ecf9d26cce91e8; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <1a0d5c74af9b6ba9ffdf1172de5a1a6df5922a00; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <344974ea1a3ca30e4920687b0091bda4438cebdb; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <7ee8f015eb47907745e2070184a8ab1e442ac3c4; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <92c4092fe012ecdfa5fb05d394f1c1d8f91ad81c; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <9b1980b6f23fa30bf12add19f37c7458625099eb; version=0b4f33def7bbde1ce2fea05f116639270e7acdc7 <c77b3b79a92e3345aa1ee296180d1af4e7031f8f; version=5.7

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

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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
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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