Linux Kernel up to 6.6.119/6.12.64/6.18.4/6.19-rc3 net/mptcp/subflow.c mptcp_disconnect state issue

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4.9$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.6.119/6.12.64/6.18.4/6.19-rc3. This affects the function mptcp_disconnect of the file net/mptcp/subflow.c. Such manipulation leads to state issue. This vulnerability is documented as CVE-2025-71144. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.119/6.12.64/6.18.4/6.19-rc3 and classified as critical. Affected by this issue is the function mptcp_disconnect of the file net/mptcp/subflow.c. The manipulation with an unknown input leads to a state issue vulnerability. Using CWE to declare the problem leads to CWE-371. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mptcp: ensure context reset on disconnect() After the blamed commit below, if the MPC subflow is already in TCP_CLOSE status or has fallback to TCP at mptcp_disconnect() time, mptcp_do_fastclose() skips setting the `send_fastclose flag` and the later __mptcp_close_ssk() does not reset anymore the related subflow context. Any later connection will be created with both the `request_mptcp` flag and the msk-level fallback status off (it is unconditionally cleared at MPTCP disconnect time), leading to a warning in subflow_data_ready(): WARNING: CPU: 26 PID: 8996 at net/mptcp/subflow.c:1519 subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Modules linked in: CPU: 26 UID: 0 PID: 8996 Comm: syz.22.39 Not tainted 6.18.0-rc7-05427-g11fc074f6c36 #1 PREEMPT(voluntary) Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:subflow_data_ready (net/mptcp/subflow.c:1519 (discriminator 13)) Code: 90 0f 0b 90 90 e9 04 fe ff ff e8 b7 1e f5 fe 89 ee bf 07 00 00 00 e8 db 19 f5 fe 83 fd 07 0f 84 35 ff ff ff e8 9d 1e f5 fe 90 <0f> 0b 90 e9 27 ff ff ff e8 8f 1e f5 fe 4c 89 e7 48 89 de e8 14 09 RSP: 0018:ffffc9002646fb30 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff88813b218000 RCX: ffffffff825c8435 RDX: ffff8881300b3580 RSI: ffffffff825c8443 RDI: 0000000000000005 RBP: 000000000000000b R08: ffffffff825c8435 R09: 000000000000000b R10: 0000000000000005 R11: 0000000000000007 R12: ffff888131ac0000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007f88330af6c0(0000) GS:ffff888a93dd2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f88330aefe8 CR3: 000000010ff59000 CR4: 0000000000350ef0 Call Trace: <TASK> tcp_data_ready (net/ipv4/tcp_input.c:5356) tcp_data_queue (net/ipv4/tcp_input.c:5445) tcp_rcv_state_process (net/ipv4/tcp_input.c:7165) tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1955) __release_sock (include/net/sock.h:1158 (discriminator 6) net/core/sock.c:3180 (discriminator 6)) release_sock (net/core/sock.c:3737) mptcp_sendmsg (net/mptcp/protocol.c:1763 net/mptcp/protocol.c:1857) inet_sendmsg (net/ipv4/af_inet.c:853 (discriminator 7)) __sys_sendto (net/socket.c:727 (discriminator 15) net/socket.c:742 (discriminator 15) net/socket.c:2244 (discriminator 15)) __x64_sys_sendto (net/socket.c:2247) do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) RIP: 0033:0x7f883326702d Address the issue setting an explicit `fastclosing` flag at fastclose time, and checking such flag after mptcp_do_fastclose().

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2025-71144 since 01/13/2026. The exploitation is known to be difficult. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/12/2026).

The vulnerability scanner Nessus provides a plugin with the ID 301875 (Oracle Linux 10 : Unbreakable Enterprise kernel (ELSA-2026-50144)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.120, 6.12.65, 6.18.5 or 6.19-rc4 eliminates this vulnerability. Applying the patch 5c7c7135468f3fc6379cde9777a2c18bfe92d82f/1c7c3a9314d8a7fc0e9a508606466a967c8e774a/f1a77dfc3b045c3dd5f6e64189b9f52b90399f07/86730ac255b0497a272704de9a1df559f5d6602e is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (301875) and CERT Bund (WID-SEC-2026-0119). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Open Source Linux Kernel

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.0
VulDB Meta Temp Score: 4.9

VulDB Base Score: 4.6
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: State issue
CWE: CWE-371
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 301875
Nessus Name: Oracle Linux 10 : Unbreakable Enterprise kernel (ELSA-2026-50144)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.120/6.12.65/6.18.5/6.19-rc4
Patch: 5c7c7135468f3fc6379cde9777a2c18bfe92d82f/1c7c3a9314d8a7fc0e9a508606466a967c8e774a/f1a77dfc3b045c3dd5f6e64189b9f52b90399f07/86730ac255b0497a272704de9a1df559f5d6602e

Timelineinfo

01/13/2026 CVE reserved
01/14/2026 +1 days Advisory disclosed
01/14/2026 +0 days VulDB entry created
03/12/2026 +57 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2025-71144 (🔒)
GCVE (CVE): GCVE-0-2025-71144
GCVE (VulDB): GCVE-100-341096
CERT Bund: WID-SEC-2026-0119 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 01/14/2026 17:52
Updated: 03/12/2026 06:33
Changes: 01/14/2026 17:52 (59), 01/16/2026 08:09 (7), 02/19/2026 19:13 (1), 02/26/2026 19:59 (11), 03/12/2026 06:33 (2)
Complete: 🔍
Cache ID: 216::103

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