Local denial of service via stale MPTCP context
Published Jan 14, 2026 · Updated Jan 14, 2026
State-management flaw in Linux Kernel MPTCP allows local users to cause a service interruption through a crafted disconnect sequence. When a subflow is already in TCP_CLOSE or has fallen back to TCP, mptcp_do_fastclose() omits the send_fastclose flag, so __mptcp_close_ssk() leaves the subflow context stale. A later connection lacks both request_mptcp and the MPTCP-socket fallback state, reaching a warning in subflow_data_ready(); low-privileged local access and MPTCP use are required, and the published impact is limited to availability.
Summary
What happened
State-management flaw in Linux Kernel MPTCP allows local users to cause a service interruption through a crafted disconnect sequence. When a subflow is already in TCP_CLOSE or has fallen back to TCP, mptcp_do_fastclose() omits the send_fastclose flag, so __mptcp_close_ssk() leaves the subflow context stale. A later connection lacks both request_mptcp and the MPTCP-socket fallback state, reaching a warning in subflow_data_ready(); low-privileged local access and MPTCP use are required, and the published impact is limited to availability.
The record
- CVE
- CVE-2025-71144
- Published
- Jan 14, 2026
- Updated
- Jan 14, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 14, 2026CVE publishedPublication date reported by the CVE source.
- Jan 14, 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.
- Affected versionversion=3a13454fd098ed51e733958488f8ec62859a9ed8 <5c7c7135468f3fc6379cde9777a2c18bfe92d82f
- Affected versionversion=6.18
- Affected versionversion=9ea05fabce31ff93a0adae8221c58bc6d7b832f3
- Affected versionversion=ae155060247be8dcae3802a95bd1bdf93ab3215d <86730ac255b0497a272704de9a1df559f5d6602e
- Affected versionversion=ae155060247be8dcae3802a95bd1bdf93ab3215d <f1a77dfc3b045c3dd5f6e64189b9f52b90399f07
- Affected versionversion=c4f7b0916b95fd2226e5ab98882482b08f52e1c0
- Affected versionversion=f6fb2cbc91a81178dea23d463503b4525a76825d <1c7c3a9314d8a7fc0e9a508606466a967c8e774a
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
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Your stack
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